fetchmail
(1)
Name
fetchmail - ble server
Synopsis
fetchmail [option...] [mailserver...]
fetchmailconf
Description
fetchmail reference manual fetchmail(1)
NAME
fetchmail - fetch mail from a POP, IMAP, ETRN, or ODMR-capa-
ble server
SYNOPSIS
fetchmail [option...] [mailserver...]
fetchmailconf
DESCRIPTION
fetchmail is a mail-retrieval and forwarding utility; it
fetches mail from remote mailservers and forwards it to your
local (client) machine's delivery system. You can then han-
dle the retrieved mail using normal mail user agents such as
mutt(1), elm(1) or Mail(1). The fetchmail utility can be
run in a daemon mode to repeatedly poll one or more systems
at a specified interval.
The fetchmail program can gather mail from servers support-
ing any of the common mail-retrieval protocols: POP2
(legacy, to be removed from future release), POP3, IMAP2bis,
IMAP4, and IMAP4rev1. It can also use the ESMTP ETRN exten-
sion and ODMR. (The RFCs describing all these protocols are
listed at the end of this manual page.)
While fetchmail is primarily intended to be used over on-
demand TCP/IP links (such as SLIP or PPP connections), it
may also be useful as a message transfer agent for sites
which refuse for security reasons to permit (sender-initi-
ated) SMTP transactions with sendmail.
SUPPORT, TROUBLESHOOTING
For troubleshooting, tracing and debugging, you need to
increase fetchmail's verbosity to actually see what happens.
To do that, please run both of the two following commands,
adding all of the options you'd normally use.
env LC_ALL=C fetchmail -V -v --nodetach --nosyslog
(This command line prints in English how fetchmail
understands your configuration.)
env LC_ALL=C fetchmail -vvv --nodetach --nosyslog
(This command line actually runs fetchmail with verbose
English output.)
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Also see
You can omit the LC_ALL=C part above if you want output in
the local language (if supported). However if you are post-
ing to mailing lists, please leave it in. The maintainers do
not necessarily understand your language, please use
English.
CONCEPTS
If fetchmail is used with a POP or an IMAP server (but not
with ETRN or ODMR), it has two fundamental modes of opera-
tion for each user account from which it retrieves mail:
singledrop- and multidrop-mode.
In singledrop-mode,
fetchmail assumes that all messages in the user's
account (mailbox) are intended for a single recipient.
The identity of the recipient will either default to
the local user currently executing fetchmail, or will
need to be explicitly specified in the configuration
file.
fetchmail uses singledrop-mode when the fetchmailrc
configuration contains at most a single local user
specification for a given server account.
In multidrop-mode,
fetchmail assumes that the mail server account actually
contains mail intended for any number of different
recipients. Therefore, fetchmail must attempt to
deduce the proper "envelope recipient" from the mail
headers of each message. In this mode of operation,
fetchmail almost resembles a mail transfer agent (MTA).
Note that neither the POP nor IMAP protocols were
intended for use in this fashion, and hence envelope
information is often not directly available. The ISP
must stores the envelope information in some message
header and. The ISP must also store one copy of the
message per recipient. If either of the conditions is
not fulfilled, this process is unreliable, because
fetchmail must then resort to guessing the true enve-
lope recipient(s) of a message. This usually fails for
mailing list messages and Bcc:d mail, or mail for mul-
tiple recipients in your domain.
fetchmail uses multidrop-mode when more than one local
user and/or a wildcard is specified for a particular
server account in the configuration file.
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In ETRN and ODMR modes,
these considerations do not apply, as these protocols
are based on SMTP, which provides explicit envelope
recipient information. These protocols always support
multiple recipients.
As each message is retrieved, fetchmail normally delivers it
via SMTP to port 25 on the machine it is running on (local-
host), just as though it were being passed in over a normal
TCP/IP link. fetchmail provides the SMTP server with an
envelope recipient derived in the manner described previ-
ously. The mail will then be delivered according to your
MTA's rules (the Mail Transfer Agent is usually sendmail(8),
exim(8), or postfix(8)). Invoking your system's MDA (Mail
Delivery Agent) is the duty of your MTA. All the delivery-
control mechanisms (such as .forward files) normally avail-
able through your system MTA and local delivery agents will
therefore be applied as usual.
If your fetchmail configuration sets a local MDA (see the
--mda option), it will be used directly instead of talking
SMTP to port 25.
If the program fetchmailconf is available, it will assist
you in setting up and editing a fetchmailrc configuration.
It runs under the X window system and requires that the lan-
guage Python and the Tk toolkit (with Python bindings) be
present on your system. If you are first setting up fetch-
mail for single-user mode, it is recommended that you use
Novice mode. Expert mode provides complete control of
fetchmail configuration, including the multidrop features.
In either case, the 'Autoprobe' button will tell you the
most capable protocol a given mailserver supports, and warn
you of potential problems with that server.
GENERAL OPERATION
The behavior of fetchmail is controlled by command-line
options and a run control file, ~/.fetchmailrc, the syntax
of which we describe in a later section (this file is what
the fetchmailconf program edits). Command-line options
override ~/.fetchmailrc declarations.
Each server name that you specify following the options on
the command line will be queried. If you don't specify any
servers on the command line, each 'poll' entry in your
~/.fetchmailrc file will be queried.
To facilitate the use of fetchmail in scripts and pipelines,
it returns an appropriate exit code upon termination -- see
EXIT CODES below.
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The following options modify the behavior of fetchmail. It
is seldom necessary to specify any of these once you have a
working .fetchmailrc file set up.
Almost all options have a corresponding keyword which can be
used to declare them in a .fetchmailrc file.
Some special options are not covered here, but are docu-
mented instead in sections on AUTHENTICATION and DAEMON MODE
which follow.
General Options
-V | --version
Displays the version information for your copy of
fetchmail. No mail fetch is performed. Instead, for
each server specified, all the option information that
would be computed if fetchmail were connecting to that
server is displayed. Any non-printables in passwords
or other string names are shown as backslashed C-like
escape sequences. This option is useful for verifying
that your options are set the way you want them.
-c | --check
Return a status code to indicate whether there is mail
waiting, without actually fetching or deleting mail
(see EXIT CODES below). This option turns off daemon
mode (in which it would be useless). It doesn't play
well with queries to multiple sites, and doesn't work
with ETRN or ODMR. It will return a false positive if
you leave read but undeleted mail in your server mail-
box and your fetch protocol can't tell kept messages
from new ones. This means it will work with IMAP, not
work with POP2, and may occasionally flake out under
POP3.
-s | --silent
Silent mode. Suppresses all progress/status messages
that are normally echoed to standard output during a
fetch (but does not suppress actual error messages).
The --verbose option overrides this.
-v | --verbose
Verbose mode. All control messages passed between
fetchmail and the mailserver are echoed to stdout.
Overrides --silent. Doubling this option (-v -v)
causes extra diagnostic information to be printed.
--nosoftbounce
(since v6.3.10, Keyword: set no softbounce, since
v6.3.10)
Hard bounce mode. All permanent delivery errors cause
messages to be deleted from the upstream server, see
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"no softbounce" below.
--softbounce
(since v6.3.10, Keyword: set softbounce, since v6.3.10)
Soft bounce mode. All permanent delivery errors cause
messages to be left on the upstream server if the pro-
tocol supports that. Default to match historic fetch-
mail documentation, to be changed to hard bounce mode
in the next fetchmail release.
Disposal Options
-a | --all | (since v6.3.3)
(Keyword: fetchall, since v3.0)
Retrieve both old (seen) and new messages from the
mailserver. The default is to fetch only messages the
server has not marked seen. Under POP3, this option
also forces the use of RETR rather than TOP. Note that
POP2 retrieval behaves as though --all is always on
(see RETRIEVAL FAILURE MODES below) and this option
does not work with ETRN or ODMR. While the -a and
--all command-line and fetchall rcfile options have
been supported for a long time, the --fetchall command-
line option was added in v6.3.3.
-k | --keep
(Keyword: keep)
Keep retrieved messages on the remote mailserver. Nor-
mally, messages are deleted from the folder on the
mailserver after they have been retrieved. Specifying
the keep option causes retrieved messages to remain in
your folder on the mailserver. This option does not
work with ETRN or ODMR. If used with POP3, it is recom-
mended to also specify the --uidl option or uidl key-
word.
-K | --nokeep
(Keyword: nokeep)
Delete retrieved messages from the remote mailserver.
This option forces retrieved mail to be deleted. It
may be useful if you have specified a default of keep
in your .fetchmailrc. This option is forced on with
ETRN and ODMR.
-F | --flush
(Keyword: flush)
POP3/IMAP only. This is a dangerous option and can
cause mail loss when used improperly. It deletes old
(seen) messages from the mailserver before retrieving
new messages. Warning: This can cause mail loss if you
check your mail with other clients than fetchmail, and
cause fetchmail to delete a message it had never
fetched before. It can also cause mail loss if the
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mail server marks the message seen after retrieval
(IMAP2 servers). You should probably not use this
option in your configuration file. If you use it with
POP3, you must use the 'uidl' option. What you probably
want is the default setting: if you don't specify '-k',
then fetchmail will automatically delete messages after
successful delivery.
--limitflush
POP3/IMAP only, since version 6.3.0. Delete oversized
messages from the mailserver before retrieving new mes-
sages. The size limit should be separately specified
with the --limit option. This option does not work
with ETRN or ODMR.
Protocol and Query Options
-p <proto> | --proto <proto> |
(Keyword: proto[col])
Specify the protocol to use when communicating with the
remote mailserver. If no protocol is specified, the
default is AUTO. proto may be one of the following:
AUTO Tries IMAP, POP3, and POP2 (skipping any of these
for which support has not been compiled in).
POP2 Post Office Protocol 2 (legacy, to be removed from
future release)
POP3 Post Office Protocol 3
APOP Use POP3 with old-fashioned MD5-challenge authen-
tication. Considered not resistant to man-in-the-
middle attacks.
RPOP Use POP3 with RPOP authentication.
KPOP Use POP3 with Kerberos V4 authentication on port
1109.
SDPS Use POP3 with Demon Internet's SDPS extensions.
IMAP IMAP2bis, IMAP4, or IMAP4rev1 (fetchmail automati-
cally detects their capabilities).
ETRN Use the ESMTP ETRN option.
ODMR Use the the On-Demand Mail Relay ESMTP profile.
All these alternatives work in basically the same way (com-
municating with standard server daemons to fetch mail
already delivered to a mailbox on the server) except ETRN
and ODMR. The ETRN mode allows you to ask a compliant ESMTP
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server (such as BSD sendmail at release 8.8.0 or higher) to
immediately open a sender-SMTP connection to your client
machine and begin forwarding any items addressed to your
client machine in the server's queue of undelivered mail.
The ODMR mode requires an ODMR-capable server and works sim-
ilarly to ETRN, except that it does not require the client
machine to have a static DNS.
-U | --uidl
(Keyword: uidl)
Force UIDL use (effective only with POP3). Force
client-side tracking of 'newness' of messages (UIDL
stands for "unique ID listing" and is described in
RFC1939). Use with 'keep' to use a mailbox as a baby
news drop for a group of users. The fact that seen mes-
sages are skipped is logged, unless error logging is
done through syslog while running in daemon mode. Note
that fetchmail may automatically enable this option
depending on upstream server capabilities. Note also
that this option may be removed and forced enabled in a
future fetchmail version. See also: --idfile.
--idle (since 6.3.3)
(Keyword: idle, since before 6.0.0)
Enable IDLE use (effective only with IMAP). Note that
this works with only one folder at a given time. While
the idle rcfile keyword had been supported for a long
time, the --idle command-line option was added in ver-
sion 6.3.3. IDLE use means that fetchmail tells the
IMAP server to send notice of new messages, so they can
be retrieved sooner than would be possible with regular
polls.
-P <portnumber> | --service <servicename>
(Keyword: service) Since version 6.3.0.
The service option permits you to specify a service
name to connect to. You can specify a decimal port
number here, if your services database lacks the
required service-port assignments. See the FAQ item R12
and the --ssl documentation for details. This replaces
the older --port option.
--port <portnumber>
(Keyword: port)
Obsolete version of --service that does not take ser-
vice names. Note: this option may be removed from a
future version.
--principal <principal>
(Keyword: principal)
The principal option permits you to specify a service
principal for mutual authentication. This is
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applicable to POP3 or IMAP with Kerberos 4 authentica-
tion only. It does not apply to Kerberos 5 or GSSAPI.
This option may be removed in a future fetchmail ver-
sion.
-t <seconds> | --timeout <seconds>
(Keyword: timeout)
The timeout option allows you to set a server-nonre-
sponse timeout in seconds. If a mailserver does not
send a greeting message or respond to commands for the
given number of seconds, fetchmail will drop the con-
nection to it. Without such a timeout fetchmail might
hang until the TCP connection times out, trying to
fetch mail from a down host, which may be very long.
This would be particularly annoying for a fetchmail
running in the background. There is a default timeout
which fetchmail -V will report. If a given connection
receives too many timeouts in succession, fetchmail
will consider it wedged and stop retrying. The calling
user will be notified by email if this happens.
Beginning with fetchmail 6.3.10, the SMTP client uses
the recommended minimum timeouts from RFC-5321 while
waiting for the SMTP/LMTP server it is talking to. You
can raise the timeouts even more, but you cannot
shorten them. This is to avoid a painful situation
where fetchmail has been configured with a short time-
out (a minute or less), ships a long message (many
MBytes) to the local MTA, which then takes longer than
timeout to respond "OK", which it eventually will; that
would mean the mail gets delivered properly, but fetch-
mail cannot notice it and will thus refetch this big
message over and over again.
--plugin <command>
(Keyword: plugin)
The plugin option allows you to use an external program
to establish the TCP connection. This is useful if you
want to use ssh, or need some special firewalling set-
up. The program will be looked up in $PATH and can
optionally be passed the hostname and port as arguments
using "%h" and "%p" respectively (note that the inter-
polation logic is rather primitive, and these tokens
must be bounded by whitespace or beginning of string or
end of string). Fetchmail will write to the plugin's
stdin and read from the plugin's stdout.
--plugout <command>
(Keyword: plugout)
Identical to the plugin option above, but this one is
used for the SMTP connections.
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-r <name> | --folder <name>
(Keyword: folder[s])
Causes a specified non-default mail folder on the
mailserver (or comma-separated list of folders) to be
retrieved. The syntax of the folder name is server-
dependent. This option is not available under POP3,
ETRN, or ODMR.
--tracepolls
(Keyword: tracepolls)
Tell fetchmail to poll trace information in the form
'polling account %s' and 'folder %s' to the Received
line it generates, where the %s parts are replaced by
the user's remote name, the poll label, and the folder
(mailbox) where available (the Received header also
normally includes the server's true name). This can be
used to facilitate mail filtering based on the account
it is being received from. The folder information is
written only since version 6.3.4.
--ssl
(Keyword: ssl)
Causes the connection to the mail server to be
encrypted via SSL. Connect to the server using the
specified base protocol over a connection secured by
SSL. This option defeats opportunistic starttls negoti-
ation. It is highly recommended to use --sslproto
'SSL3' --sslcertck to validate the certificates pre-
sented by the server and defeat the obsolete SSLv2
negotiation. More information is available in the
README.SSL file that ships with fetchmail.
Note that fetchmail may still try to negotiate SSL
through starttls even if this option is omitted. You
can use the --sslproto option to defeat this behavior
or tell fetchmail to negotiate a particular SSL proto-
col.
If no port is specified, the connection is attempted to
the well known port of the SSL version of the base pro-
tocol. This is generally a different port than the
port used by the base protocol. For IMAP, this is port
143 for the clear protocol and port 993 for the SSL
secured protocol, for POP3, it is port 110 for the
clear text and port 995 for the encrypted variant.
If your system lacks the corresponding entries from
/etc/services, see the --service option and specify the
numeric port number as given in the previous paragraph
(unless your ISP had directed you to different ports,
which is uncommon however).
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--sslcert <name>
(Keyword: sslcert)
For certificate-based client authentication. Some SSL
encrypted servers require client side keys and certifi-
cates for authentication. In most cases, this is
optional. This specifies the location of the public
key certificate to be presented to the server at the
time the SSL session is established. It is not
required (but may be provided) if the server does not
require it. It may be the same file as the private key
(combined key and certificate file) but this is not
recommended. Also see --sslkey below.
NOTE: If you use client authentication, the user name
is fetched from the certificate's CommonName and over-
rides the name set with --user.
--sslkey <name>
(Keyword: sslkey)
Specifies the file name of the client side private SSL
key. Some SSL encrypted servers require client side
keys and certificates for authentication. In most
cases, this is optional. This specifies the location
of the private key used to sign transactions with the
server at the time the SSL session is established. It
is not required (but may be provided) if the server
does not require it. It may be the same file as the
public key (combined key and certificate file) but this
is not recommended.
If a password is required to unlock the key, it will be
prompted for at the time just prior to establishing the
session to the server. This can cause some complica-
tions in daemon mode.
Also see --sslcert above.
--sslproto <name>
(Keyword: sslproto)
Forces an SSL/TLS protocol. Possible values are '',
'SSL2' (not supported on all systems), 'SSL23', (use of
these two values is discouraged and should only be used
as a last resort) 'SSL3', and 'TLS1'. The default be-
haviour if this option is unset is: for connections
without --ssl, use 'TLS1' so that fetchmail will oppor-
tunistically try STARTTLS negotiation with TLS1. You
can configure this option explicitly if the default
handshake (TLS1 if --ssl is not used) does not work for
your server.
Use this option with 'TLS1' value to enforce a STARTTLS
connection. In this mode, it is highly recommended to
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also use --sslcertck (see below). Note that this will
then cause fetchmail v6.3.19 to force STARTTLS negotia-
tion even if it is not advertised by the server.
To defeat opportunistic TLSv1 negotiation when the
server advertises STARTTLS or STLS, and use a cleartext
connection use ''. This option, even if the argument
is the empty string, will also suppress the diagnostic
'SERVER: opportunistic upgrade to TLS.' message in ver-
bose mode. The default is to try appropriate protocols
depending on context.
--sslcertck
(Keyword: sslcertck)
Causes fetchmail to strictly check the server certifi-
cate against a set of local trusted certificates (see
the sslcertfile and sslcertpath options). If the server
certificate cannot be obtained or is not signed by one
of the trusted ones (directly or indirectly), the SSL
connection will fail, regardless of the sslfingerprint
option.
Note that CRL (certificate revocation lists) are only
supported in OpenSSL 0.9.7 and newer! Your system clock
should also be reasonably accurate when using this
option.
Note that this optional behavior may become default
behavior in future fetchmail versions.
--sslcertfile <file>
(Keyword: sslcertfile, since v6.3.17)
Sets the file fetchmail uses to look up local certifi-
cates. The default is empty. This can be given in
addition to --sslcertpath below, and certificates spec-
ified in --sslcertfile will be processed before those
in --sslcertpath. The option can be used in addition
to --sslcertpath.
The file is a text file. It contains the concatenation
of trusted CA certificates in PEM format.
Note that using this option will suppress loading the
default SSL trusted CA certificates file unless you set
the environment variable FETCH-
MAIL_INCLUDE_DEFAULT_X509_CA_CERTS to a non-empty
value.
--sslcertpath <directory>
(Keyword: sslcertpath)
Sets the directory fetchmail uses to look up local cer-
tificates. The default is your OpenSSL default
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directory. The directory must be hashed the way OpenSSL
expects it - every time you add or modify a certificate
in the directory, you need to use the c_rehash tool
(which comes with OpenSSL in the tools/ subdirectory).
Also, after OpenSSL upgrades, you may need to run
c_rehash; particularly when upgrading from 0.9.X to
1.0.0.
This can be given in addition to --sslcertfile above,
which see for precedence rules.
Note that using this option will suppress adding the
default SSL trusted CA certificates directory unless
you set the environment variable FETCH-
MAIL_INCLUDE_DEFAULT_X509_CA_CERTS to a non-empty
value.
--sslcommonname <common name>
(Keyword: sslcommonname; since v6.3.9)
Use of this option is discouraged. Before using it,
contact the administrator of your upstream server and
ask for a proper SSL certificate to be used. If that
cannot be attained, this option can be used to specify
the name (CommonName) that fetchmail expects on the
server certificate. A correctly configured server will
have this set to the hostname by which it is reached,
and by default fetchmail will expect as much. Use this
option when the CommonName is set to some other value,
to avoid the "Server CommonName mismatch" warning, and
only if the upstream server can't be made to use proper
certificates.
--sslfingerprint <fingerprint>
(Keyword: sslfingerprint)
Specify the fingerprint of the server key (an MD5 hash
of the key) in hexadecimal notation with colons sepa-
rating groups of two digits. The letter hex digits must
be in upper case. This is the default format OpenSSL
uses, and the one fetchmail uses to report the finger-
print when an SSL connection is established. When this
is specified, fetchmail will compare the server key
fingerprint with the given one, and the connection will
fail if they do not match regardless of the sslcertck
setting. The connection will also fail if fetchmail
cannot obtain an SSL certificate from the server. This
can be used to prevent man-in-the-middle attacks, but
the finger print from the server needs to be obtained
or verified over a secure channel, and certainly not
over the same Internet connection that fetchmail would
use.
Using this option will prevent printing certificate
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verification errors as long as --sslcertck is unset.
To obtain the fingerprint of a certificate stored in
the file cert.pem, try:
openssl x509 -in cert.pem -noout -md5 -fingerprint
For details, see x509(1ssl).
Delivery Control Options
-S <hosts> | --smtphost <hosts>
(Keyword: smtp[host])
Specify a hunt list of hosts to forward mail to (one or
more hostnames, comma-separated). Hosts are tried in
list order; the first one that is up becomes the for-
warding target for the current run. If this option is
not specified, 'localhost' is used as the default.
Each hostname may have a port number following the host
name. The port number is separated from the host name
by a slash; the default port is "smtp". If you specify
an absolute path name (beginning with a /), it will be
interpreted as the name of a UNIX socket accepting LMTP
connections (such as is supported by the Cyrus IMAP
daemon) Example:
--smtphost server1,server2/2525,server3,/var/imap/socket/lmtp
This option can be used with ODMR, and will make fetch-
mail a relay between the ODMR server and SMTP or LMTP
receiver.
--fetchdomains <hosts>
(Keyword: fetchdomains)
In ETRN or ODMR mode, this option specifies the list of
domains the server should ship mail for once the con-
nection is turned around. The default is the FQDN of
the machine running fetchmail.
-D <domain> | --smtpaddress <domain>
(Keyword: smtpaddress)
Specify the domain to be appended to addresses in RCPT
TO lines shipped to SMTP. When this is not specified,
the name of the SMTP server (as specified by --smt-
phost) is used for SMTP/LMTP and 'localhost' is used
for UNIX socket/BSMTP.
--smtpname <user@domain>
(Keyword: smtpname)
Specify the domain and user to be put in RCPT TO lines
shipped to SMTP. The default user is the current local
user.
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-Z <nnn> | --antispam <nnn[, nnn]...>
(Keyword: antispam)
Specifies the list of numeric SMTP errors that are to
be interpreted as a spam-block response from the lis-
tener. A value of -1 disables this option. For the
command-line option, the list values should be comma-
separated.
-m <command> | --mda <command>
(Keyword: mda)
This option lets fetchmail use a Message or Local
Delivery Agent (MDA or LDA) directly, rather than for-
ward via SMTP or LMTP.
To avoid losing mail, use this option only with MDAs
like maildrop or MTAs like sendmail that exit with a
nonzero status on disk-full and other delivery errors;
the nonzero status tells fetchmail that delivery failed
and prevents the message from being deleted on the
server.
If fetchmail is running as root, it sets its user id
while delivering mail through an MDA as follows:
First, the FETCHMAILUSER, LOGNAME, and USER environment
variables are checked in this order. The value of the
first variable from his list that is defined (even if
it is empty!) is looked up in the system user database.
If none of the variables is defined, fetchmail will use
the real user id it was started with. If one of the
variables was defined, but the user stated there isn't
found, fetchmail continues running as root, without
checking remaining variables on the list. Practically,
this means that if you run fetchmail as root (not rec-
ommended), it is most useful to define the FETCH-
MAILUSER environment variable to set the user that the
MDA should run as. Some MDAs (such as maildrop) are
designed to be setuid root and setuid to the recipi-
ent's user id, so you don't lose functionality this way
even when running fetchmail as unprivileged user.
Check the MDA's manual for details.
Some possible MDAs are "/usr/sbin/sendmail -i -f %F --
%T" (Note: some several older or vendor sendmail ver-
sions mistake -- for an address, rather than an indica-
tor to mark the end of the option arguments),
"/usr/bin/deliver" and "/usr/bin/maildrop -d %T".
Local delivery addresses will be inserted into the MDA
command wherever you place a %T; the mail message's
From address will be inserted where you place an %F.
Do NOT enclose the %F or %T string in single quotes!
For both %T and %F, fetchmail encloses the addresses in
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fetchmail reference manual fetchmail(1)
single quotes ('), after removing any single quotes
they may contain, before the MDA command is passed to
the shell.
Do NOT use an MDA invocation that dispatches on the
contents of To/Cc/Bcc, like "sendmail -i -t" or "qmail-
inject", it will create mail loops and bring the just
wrath of many postmasters down upon your head. This is
one of the most frequent configuration errors!
Also, do not try to combine multidrop mode with an MDA
such as maildrop that can only accept one address,
unless your upstream stores one copy of the message per
recipient and transports the envelope recipient in a
header; you will lose mail.
The well-known procmail(1) package is very hard to con-
figure properly, it has a very nasty "fall through to
the next rule" behavior on delivery errors (even tempo-
rary ones, such as out of disk space if another user's
mail daemon copies the mailbox around to purge old mes-
sages), so your mail will end up in the wrong mailbox
sooner or later. The proper procmail configuration is
outside the scope of this document. Using maildrop(1)
is usually much easier, and many users find the filter
syntax used by maildrop easier to understand.
Finally, we strongly advise that you do not use qmail-
inject. The command line interface is non-standard
without providing benefits for typical use, and fetch-
mail makes no attempts to accommodate qmail-inject's
deviations from the standard. Some of qmail-inject's
command-line and environment options are actually dan-
gerous and can cause broken threads, non-detected
duplicate messages and forwarding loops.
--lmtp
(Keyword: lmtp)
Cause delivery via LMTP (Local Mail Transfer Protocol).
A service host and port must be explicitly specified on
each host in the smtphost hunt list (see above) if this
option is selected; the default port 25 will (in accor-
dance with RFC 2033) not be accepted.
--bsmtp <filename>
(Keyword: bsmtp)
Append fetched mail to a BSMTP file. This simply con-
tains the SMTP commands that would normally be gener-
ated by fetchmail when passing mail to an SMTP listener
daemon.
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An argument of '-' causes the SMTP batch to be written
to standard output, which is of limited use: this only
makes sense for debugging, because fetchmail's regular
output is interspersed on the same channel, so this
isn't suitable for mail delivery. This special mode may
be removed in a later release.
Note that fetchmail's reconstruction of MAIL FROM and
RCPT TO lines is not guaranteed correct; the caveats
discussed under THE USE AND ABUSE OF MULTIDROP MAIL-
BOXES below apply. This mode has precedence before
--mda and SMTP/LMTP.
--bad-header {reject|accept}
(Keyword: bad-header; since v6.3.15)
Specify how fetchmail is supposed to treat messages
with bad headers, i. e. headers with bad syntax. Tradi-
tionally, fetchmail has rejected such messages, but
some distributors modified fetchmail to accept them.
You can now configure fetchmail's behaviour per server.
Resource Limit Control Options
-l <maxbytes> | --limit <maxbytes>
(Keyword: limit)
Takes a maximum octet size argument, where 0 is the
default and also the special value designating "no
limit". If nonzero, messages larger than this size
will not be fetched and will be left on the server (in
foreground sessions, the progress messages will note
that they are "oversized"). If the fetch protocol per-
mits (in particular, under IMAP or POP3 without the
fetchall option) the message will not be marked seen.
An explicit --limit of 0 overrides any limits set in
your run control file. This option is intended for
those needing to strictly control fetch time due to
expensive and variable phone rates.
Combined with --limitflush, it can be used to delete
oversized messages waiting on a server. In daemon
mode, oversize notifications are mailed to the calling
user (see the --warnings option). This option does not
work with ETRN or ODMR.
-w <interval> | --warnings <interval>
(Keyword: warnings)
Takes an interval in seconds. When you call fetchmail
with a 'limit' option in daemon mode, this controls the
interval at which warnings about oversized messages are
mailed to the calling user (or the user specified by
the 'postmaster' option). One such notification is
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fetchmail reference manual fetchmail(1)
always mailed at the end of the the first poll that the
oversized message is detected. Thereafter, re-notifi-
cation is suppressed until after the warning interval
elapses (it will take place at the end of the first
following poll).
-b <count> | --batchlimit <count>
(Keyword: batchlimit)
Specify the maximum number of messages that will be
shipped to an SMTP listener before the connection is
deliberately torn down and rebuilt (defaults to 0,
meaning no limit). An explicit --batchlimit of 0 over-
rides any limits set in your run control file. While
sendmail(8) normally initiates delivery of a message
immediately after receiving the message terminator,
some SMTP listeners are not so prompt. MTAs like
smail(8) may wait till the delivery socket is shut down
to deliver. This may produce annoying delays when
fetchmail is processing very large batches. Setting
the batch limit to some nonzero size will prevent these
delays. This option does not work with ETRN or ODMR.
-B <number> | --fetchlimit <number>
(Keyword: fetchlimit)
Limit the number of messages accepted from a given
server in a single poll. By default there is no limit.
An explicit --fetchlimit of 0 overrides any limits set
in your run control file. This option does not work
with ETRN or ODMR.
--fetchsizelimit <number>
(Keyword: fetchsizelimit)
Limit the number of sizes of messages accepted from a
given server in a single transaction. This option is
useful in reducing the delay in downloading the first
mail when there are too many mails in the mailbox. By
default, the limit is 100. If set to 0, sizes of all
messages are downloaded at the start. This option does
not work with ETRN or ODMR. For POP3, the only valid
non-zero value is 1.
--fastuidl <number>
(Keyword: fastuidl)
Do a binary instead of linear search for the first
unseen UID. Binary search avoids downloading the UIDs
of all mails. This saves time (especially in daemon
mode) where downloading the same set of UIDs in each
poll is a waste of bandwidth. The number 'n' indicates
how rarely a linear search should be done. In daemon
mode, linear search is used once followed by binary
searches in 'n-1' polls if 'n' is greater than 1;
binary search is always used if 'n' is 1; linear search
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fetchmail reference manual fetchmail(1)
is always used if 'n' is 0. In non-daemon mode, binary
search is used if 'n' is 1; otherwise linear search is
used. The default value of 'n' is 4. This option works
with POP3 only.
-e <count> | --expunge <count>
(Keyword: expunge)
Arrange for deletions to be made final after a given
number of messages. Under POP2 or POP3, fetchmail can-
not make deletions final without sending QUIT and end-
ing the session -- with this option on, fetchmail will
break a long mail retrieval session into multiple sub-
sessions, sending QUIT after each sub-session. This is
a good defense against line drops on POP3 servers.
Under IMAP, fetchmail normally issues an EXPUNGE com-
mand after each deletion in order to force the deletion
to be done immediately. This is safest when your con-
nection to the server is flaky and expensive, as it
avoids resending duplicate mail after a line hit. How-
ever, on large mailboxes the overhead of re-indexing
after every message can slam the server pretty hard, so
if your connection is reliable it is good to do
expunges less frequently. Also note that some servers
enforce a delay of a few seconds after each quit, so
fetchmail may not be able to get back in immediately
after an expunge -- you may see "lock busy" errors if
this happens. If you specify this option to an integer
N, it tells fetchmail to only issue expunges on every
Nth delete. An argument of zero suppresses expunges
entirely (so no expunges at all will be done until the
end of run). This option does not work with ETRN or
ODMR.
Authentication Options
-u <name> | --user <name> |
(Keyword: user[name])
Specifies the user identification to be used when log-
ging in to the mailserver. The appropriate user iden-
tification is both server and user-dependent. The
default is your login name on the client machine that
is running fetchmail. See USER AUTHENTICATION below
for a complete description.
-I <specification> | --interface <specification>
(Keyword: interface)
Require that a specific interface device be up and have
a specific local or remote IPv4 (IPv6 is not supported
by this option yet) address (or range) before polling.
Frequently fetchmail is used over a transient point-to-
point TCP/IP link established directly to a mailserver
via SLIP or PPP. That is a relatively secure channel.
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fetchmail reference manual fetchmail(1)
But when other TCP/IP routes to the mailserver exist
(e.g. when the link is connected to an alternate ISP),
your username and password may be vulnerable to snoop-
ing (especially when daemon mode automatically polls
for mail, shipping a clear password over the net at
predictable intervals). The --interface option may be
used to prevent this. When the specified link is not
up or is not connected to a matching IP address,
polling will be skipped. The format is:
interface/iii.iii.iii.iii[/mmm.mmm.mmm.mmm]
The field before the first slash is the interface name
(i.e. sl0, ppp0 etc.). The field before the second
slash is the acceptable IP address. The field after
the second slash is a mask which specifies a range of
IP addresses to accept. If no mask is present
255.255.255.255 is assumed (i.e. an exact match). This
option is currently only supported under Linux and
FreeBSD. Please see the monitor section for below for
FreeBSD specific information.
Note that this option may be removed from a future
fetchmail version.
-M <interface> | --monitor <interface>
(Keyword: monitor)
Daemon mode can cause transient links which are auto-
matically taken down after a period of inactivity (e.g.
PPP links) to remain up indefinitely. This option
identifies a system TCP/IP interface to be monitored
for activity. After each poll interval, if the link is
up but no other activity has occurred on the link, then
the poll will be skipped. However, when fetchmail is
woken up by a signal, the monitor check is skipped and
the poll goes through unconditionally. This option is
currently only supported under Linux and FreeBSD. For
the monitor and interface options to work for non root
users under FreeBSD, the fetchmail binary must be
installed SGID kmem. This would be a security hole,
but fetchmail runs with the effective GID set to that
of the kmem group only when interface data is being
collected.
Note that this option may be removed from a future
fetchmail version.
--auth <type>
(Keyword: auth[enticate])
This option permits you to specify an authentication
type (see USER AUTHENTICATION below for details). The
possible values are any, password, kerberos_v5,
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fetchmail reference manual fetchmail(1)
kerberos (or, for excruciating exactness, kerberos_v4),
gssapi, cram-md5, otp, ntlm, msn (only for POP3),
external (only IMAP) and ssh. When any (the default)
is specified, fetchmail tries first methods that don't
require a password (EXTERNAL, GSSAPI, KERBEROS IV, KER-
BEROS 5); then it looks for methods that mask your
password (CRAM-MD5, NTLM, X-OTP - note that MSN is only
supported for POP3, but not autoprobed); and only if
the server doesn't support any of those will it ship
your password en clair. Other values may be used to
force various authentication methods (ssh suppresses
authentication and is thus useful for IMAP PREAUTH).
(external suppresses authentication and is thus useful
for IMAP EXTERNAL). Any value other than password,
cram-md5, ntlm, msn or otp suppresses fetchmail's nor-
mal inquiry for a password. Specify ssh when you are
using an end-to-end secure connection such as an ssh
tunnel; specify external when you use TLS with client
authentication and specify gssapi or kerberos_v4 if you
are using a protocol variant that employs GSSAPI or K4.
Choosing KPOP protocol automatically selects Kerberos
authentication. This option does not work with ETRN.
GSSAPI service names are in line with RFC-2743 and IANA
registrations, see
Miscellaneous Options
-f <pathname> | --fetchmailrc <pathname>
Specify a non-default name for the ~/.fetchmailrc run
control file. The pathname argument must be either "-"
(a single dash, meaning to read the configuration from
standard input) or a filename. Unless the --version
option is also on, a named file argument must have per-
missions no more open than 0700 (u=rwx,g=,o=) or else
be /dev/null.
-i <pathname> | --idfile <pathname>
(Keyword: idfile)
Specify an alternate name for the .fetchids file used
to save message UIDs. NOTE: since fetchmail 6.3.0,
write access to the directory containing the idfile is
required, as fetchmail writes a temporary file and
renames it into the place of the real idfile only if
the temporary file has been written successfully. This
avoids the truncation of idfiles when running out of
disk space.
--pidfile <pathname>
(Keyword: pidfile; since fetchmail v6.3.4)
Override the default location of the PID file. Default:
see "ENVIRONMENT" below.
-n | --norewrite
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fetchmail reference manual fetchmail(1)
(Keyword: no rewrite)
Normally, fetchmail edits RFC-822 address headers (To,
From, Cc, Bcc, and Reply-To) in fetched mail so that
any mail IDs local to the server are expanded to full
addresses (@ and the mailserver hostname are appended).
This enables replies on the client to get addressed
correctly (otherwise your mailer might think they
should be addressed to local users on the client
machine!). This option disables the rewrite. (This
option is provided to pacify people who are paranoid
about having an MTA edit mail headers and want to know
they can prevent it, but it is generally not a good
idea to actually turn off rewrite.) When using ETRN or
ODMR, the rewrite option is ineffective.
-E <line> | --envelope <line>
(Keyword: envelope; Multidrop only)
In the configuration file, an enhanced syntax is used:
envelope [<count>] <line>
This option changes the header fetchmail assumes will
carry a copy of the mail's envelope address. Normally
this is 'X-Envelope-To'. Other typically found headers
to carry envelope information are 'X-Original-To' and
'Delivered-To'. Now, since these headers are not stan-
dardized, practice varies. See the discussion of mul-
tidrop address handling below. As a special case,
'envelope "Received"' enables parsing of sendmail-style
Received lines. This is the default, but discouraged
because it is not fully reliable.
Note that fetchmail expects the Received-line to be in
a specific format: It must contain "by host for
address", where host must match one of the mailserver
names that fetchmail recognizes for the account in
question.
The optional count argument (only available in the con-
figuration file) determines how many header lines of
this kind are skipped. A count of 1 means: skip the
first, take the second. A count of 2 means: skip the
first and second, take the third, and so on.
-Q <prefix> | --qvirtual <prefix>
(Keyword: qvirtual; Multidrop only)
The string prefix assigned to this option will be
removed from the user name found in the header speci-
fied with the envelope option (before doing multidrop
name mapping or localdomain checking, if either is
applicable). This option is useful if you are using
fetchmail to collect the mail for an entire domain and
your ISP (or your mail redirection provider) is using
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fetchmail reference manual fetchmail(1)
qmail. One of the basic features of qmail is the
Delivered-To: message header. Whenever qmail delivers
a message to a local mailbox it puts the username and
hostname of the envelope recipient on this line. The
major reason for this is to prevent mail loops. To set
up qmail to batch mail for a disconnected site the ISP-
mailhost will have normally put that site in its 'Vir-
tualhosts' control file so it will add a prefix to all
mail addresses for this site. This results in mail sent
to 'username@userhost.userdom.dom.com' having a Deliv-
ered-To: line of the form:
Delivered-To: mbox-userstr-username@userhost.exam-
ple.com
The ISP can make the 'mbox-userstr-' prefix anything they
choose but a string matching the user host name is likely.
By using the option 'envelope Delivered-To:' you can make
fetchmail reliably identify the original envelope recipient,
but you have to strip the 'mbox-userstr-' prefix to deliver
to the correct user. This is what this option is for.
--configdump
Parse the ~/.fetchmailrc file, interpret any command-
line options specified, and dump a configuration report
to standard output. The configuration report is a data
structure assignment in the language Python. This
option is meant to be used with an interactive
~/.fetchmailrc editor like fetchmailconf, written in
Python.
Removed Options
-T | --netsec
Removed before version 6.3.0, the required underlying
inet6_apps library had been discontinued and is no
longer available.
USER AUTHENTICATION AND ENCRYPTION
All modes except ETRN require authentication of the client
to the server. Normal user authentication in fetchmail is
very much like the authentication mechanism of ftp(1). The
correct user-id and password depend upon the underlying
security system at the mailserver.
If the mailserver is a Unix machine on which you have an
ordinary user account, your regular login name and password
are used with fetchmail. If you use the same login name on
both the server and the client machines, you needn't worry
about specifying a user-id with the -u option -- the default
behavior is to use your login name on the client machine as
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fetchmail reference manual fetchmail(1)
the user-id on the server machine. If you use a different
login name on the server machine, specify that login name
with the -u option. e.g. if your login name is 'jsmith' on
a machine named 'mailgrunt', you would start fetchmail as
follows:
fetchmail -u jsmith mailgrunt
The default behavior of fetchmail is to prompt you for your
mailserver password before the connection is established.
This is the safest way to use fetchmail and ensures that
your password will not be compromised. You may also specify
your password in your ~/.fetchmailrc file. This is conve-
nient when using fetchmail in daemon mode or with scripts.
Using netrc files
If you do not specify a password, and fetchmail cannot
extract one from your ~/.fetchmailrc file, it will look for
a ~/.netrc file in your home directory before requesting one
interactively; if an entry matching the mailserver is found
in that file, the password will be used. Fetchmail first
looks for a match on poll name; if it finds none, it checks
for a match on via name. See the ftp(1) man page for
details of the syntax of the ~/.netrc file. To show a prac-
tical example, a .netrc might look like this:
machine hermes.example.org
login joe
password topsecret
You can repeat this block with different user information if
you need to provide more than one password.
This feature may allow you to avoid duplicating password
information in more than one file.
On mailservers that do not provide ordinary user accounts,
your user-id and password are usually assigned by the server
administrator when you apply for a mailbox on the server.
Contact your server administrator if you don't know the cor-
rect user-id and password for your mailbox account.
POP3 VARIANTS
Early versions of POP3 (RFC1081, RFC1225) supported a crude
form of independent authentication using the .rhosts file on
the mailserver side. Under this RPOP variant, a fixed per-
user ID equivalent to a password was sent in clear over a
link to a reserved port, with the command RPOP rather than
PASS to alert the server that it should do special checking.
RPOP is supported by fetchmail (you can specify 'protocol
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fetchmail reference manual fetchmail(1)
RPOP' to have the program send 'RPOP' rather than 'PASS')
but its use is strongly discouraged, and support will be
removed from a future fetchmail version. This facility was
vulnerable to spoofing and was withdrawn in RFC1460.
RFC1460 introduced APOP authentication. In this variant of
POP3, you register an APOP password on your server host (on
some servers, the program to do this is called popauth(8)).
You put the same password in your ~/.fetchmailrc file. Each
time fetchmail logs in, it sends an MD5 hash of your pass-
word and the server greeting time to the server, which can
verify it by checking its authorization database.
Note that APOP is no longer considered resistant against
man-in-the-middle attacks.
RETR or TOP
fetchmail makes some efforts to make the server believe mes-
sages had not been retrieved, by using the TOP command with
a large number of lines when possible. TOP is a command
that retrieves the full header and a fetchmail-specified
amount of body lines. It is optional and therefore not
implemented by all servers, and some are known to implement
it improperly. On many servers however, the RETR command
which retrieves the full message with header and body, sets
the "seen" flag (for instance, in a web interface), whereas
the TOP command does not do that.
fetchmail will always use the RETR command if "fetchall" is
set. fetchmail will also use the RETR command if "keep" is
set and "uidl" is unset. Finally, fetchmail will use the
RETR command on Maillennium POP3/PROXY servers (used by Com-
cast) to avoid a deliberate TOP misinterpretation in this
server that causes message corruption.
In all other cases, fetchmail will use the TOP command. This
implies that in "keep" setups, "uidl" must be set if "TOP"
is desired.
Note that this description is true for the current version
of fetchmail, but the behavior may change in future ver-
sions. In particular, fetchmail may prefer the RETR command
because the TOP command causes much grief on some servers
and is only optional.
ALTERNATE AUTHENTICATION FORMS
If your fetchmail was built with Kerberos support and you
specify Kerberos authentication (either with --auth or the
.fetchmailrc option authenticate kerberos_v4) it will try to
get a Kerberos ticket from the mailserver at the start of
each query. Note: if either the pollname or via name is
'hesiod', fetchmail will try to use Hesiod to look up the
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fetchmail reference manual fetchmail(1)
mailserver.
If you use POP3 or IMAP with GSSAPI authentication, fetch-
mail will expect the server to have RFC1731- or RFC1734-con-
forming GSSAPI capability, and will use it. Currently this
has only been tested over Kerberos V, so you're expected to
already have a ticket-granting ticket. You may pass a user-
name different from your principal name using the standard
--user command or by the .fetchmailrc option user.
If your IMAP daemon returns the PREAUTH response in its
greeting line, fetchmail will notice this and skip the nor-
mal authentication step. This can be useful, e.g. if you
start imapd explicitly using ssh. In this case you can
declare the authentication value 'ssh' on that site entry to
stop .fetchmail from asking you for a password when it
starts up.
If you use client authentication with TLS1 and your IMAP
daemon returns the AUTH=EXTERNAL response, fetchmail will
notice this and will use the authentication shortcut and
will not send the passphrase. In this case you can declare
the authentication value 'external'
on that site to stop fetchmail from asking you for a pass-
word when it starts up.
If you are using POP3, and the server issues a one-time-
password challenge conforming to RFC1938, fetchmail will use
your password as a pass phrase to generate the required
response. This avoids sending secrets over the net unen-
crypted.
Compuserve's RPA authentication is supported. If you compile
in the support, fetchmail will try to perform an RPA pass-
phrase authentication instead of sending over the password
en clair if it detects "@compuserve.com" in the hostname.
If you are using IMAP, Microsoft's NTLM authentication (used
by Microsoft Exchange) is supported. If you compile in the
support, fetchmail will try to perform an NTLM authentica-
tion (instead of sending over the password en clair) when-
ever the server returns AUTH=NTLM in its capability
response. Specify a user option value that looks like
'user@domain': the part to the left of the @ will be passed
as the username and the part to the right as the NTLM
domain.
Secure Socket Layers (SSL) and Transport
Note that fetchmail currently uses the OpenSSL library,
which is severely underdocumented, so failures may occur
just because the programmers are not aware of OpenSSL's
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fetchmail reference manual fetchmail(1)
requirement of the day. For instance, since v6.3.16, fetch-
mail calls OpenSSL_add_all_algorithms(), which is necessary
to support certificates with SHA256 on OpenSSL 0.9.8 -- this
information is deeply hidden in the documentation and not at
all obvious. Please do not hesitate to report subtle SSL
failures.
You can access SSL encrypted services by specifying the
--ssl option. You can also do this using the "ssl" user
option in the .fetchmailrc file. With SSL encryption
enabled, queries are initiated over a connection after nego-
tiating an SSL session, and the connection fails if SSL can-
not be negotiated. Some services, such as POP3 and IMAP,
have different well known ports defined for the SSL
encrypted services. The encrypted ports will be selected
automatically when SSL is enabled and no explicit port is
specified. The --sslproto 'SSL3' option should be used to
select the SSLv3 protocol (default if unset: v2 or v3).
Also, the --sslcertck command line or sslcertck run control
file option should be used to force strict certificate
checking - see below.
If SSL is not configured, fetchmail will usually opportunis-
tically try to use STARTTLS. STARTTLS can be enforced by
using --sslproto "TLS1". TLS connections use the same port
as the unencrypted version of the protocol and negotiate TLS
via special command. The --sslcertck command line or
sslcertck run control file option should be used to force
strict certificate checking - see below.
--sslcertck is recommended: When connecting to an SSL or TLS
encrypted server, the server presents a certificate to the
client for validation. The certificate is checked to verify
that the common name in the certificate matches the name of
the server being contacted and that the effective and expi-
ration dates in the certificate indicate that it is cur-
rently valid. If any of these checks fail, a warning mes-
sage is printed, but the connection continues. The server
certificate does not need to be signed by any specific Cer-
tifying Authority and may be a "self-signed" certificate. If
the --sslcertck command line option or sslcertck run control
file option is used, fetchmail will instead abort if any of
these checks fail, because it must assume that there is a
man-in-the-middle attack in this scenario, hence fetchmail
must not expose cleartext passwords. Use of the sslcertck or
--sslcertck option is therefore advised.
Some SSL encrypted servers may request a client side cer-
tificate. A client side public SSL certificate and private
SSL key may be specified. If requested by the server, the
client certificate is sent to the server for validation.
Some servers may require a valid client certificate and may
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fetchmail reference manual fetchmail(1)
refuse connections if a certificate is not provided or if
the certificate is not valid. Some servers may require
client side certificates be signed by a recognized Certify-
ing Authority. The format for the key files and the cer-
tificate files is that required by the underlying SSL
libraries (OpenSSL in the general case).
A word of care about the use of SSL: While above mentioned
setup with self-signed server certificates retrieved over
the wires can protect you from a passive eavesdropper, it
doesn't help against an active attacker. It's clearly an
improvement over sending the passwords in clear, but you
should be aware that a man-in-the-middle attack is trivially
possible (in particular with tools such as ). Use of strict
certificate checking with a certification authority recog-
nized by server and client, or perhaps of an SSH tunnel (see
below for some examples) is preferable if you care seriously
about the security of your mailbox and passwords.
ESMTP AUTH
fetchmail also supports authentication to the ESMTP server
on the client side according to RFC 2554. You can specify a
name/password pair to be used with the keywords 'esmtpname'
and 'esmtppassword'; the former defaults to the username of
the calling user.
DAEMON MODE
Introducing the daemon mode
In daemon mode, fetchmail puts itself into the background
and runs forever, querying each specified host and then
sleeping for a given polling interval.
Starting the daemon mode
There are several ways to make fetchmail work in daemon
mode. On the command line, --daemon <interval> or -d <inter-
val> option runs fetchmail in daemon mode. You must specify
a numeric argument which is a polling interval (time to wait
after completing a whole poll cycle with the last server and
before starting the next poll cycle with the first server)
in seconds.
Example: simply invoking
fetchmail -d 900
will, therefore, poll all the hosts described in your
~/.fetchmailrc file (except those explicitly excluded with
the 'skip' verb) a bit less often than once every 15 minutes
(exactly: 15 minutes + time that the poll takes).
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It is also possible to set a polling interval in your
~/.fetchmailrc file by saying 'set daemon <interval>', where
<interval> is an integer number of seconds. If you do this,
fetchmail will always start in daemon mode unless you over-
ride it with the command-line option --daemon 0 or -d0.
Only one daemon process is permitted per user; in daemon
mode, fetchmail sets up a per-user lockfile to guarantee
this. (You can however cheat and set the FETCHMAILHOME
environment variable to overcome this setting, but in that
case, it is your responsibility to make sure you aren't
polling the same server with two processes at the same
time.)
Awakening the background daemon
Normally, calling fetchmail with a daemon in the background
sends a wake-up signal to the daemon and quits without out-
put. The background daemon then starts its next poll cycle
immediately. The wake-up signal, SIGUSR1, can also be sent
manually. The wake-up action also clears any 'wedged' flags
indicating that connections have wedged due to failed
authentication or multiple timeouts.
Terminating the background daemon
The option --quit will kill a running daemon process instead
of waking it up (if there is no such process, fetchmail will
notify you). If the --quit option appears last on the com-
mand line, fetchmail will kill the running daemon process
and then quit. Otherwise, fetchmail will first kill a run-
ning daemon process and then continue running with the other
options.
Useful options for daemon mode
The -L <filename> or --logfile <filename> option (keyword:
set logfile) is only effective when fetchmail is detached
and in daemon mode. Note that the logfile must exist before
fetchmail is run, you can use the touch(1) command with the
filename as its sole argument to create it.
This option allows you to redirect status messages into a
specified logfile (follow the option with the logfile name).
The logfile is opened for append, so previous messages
aren't deleted. This is primarily useful for debugging con-
figurations. Note that fetchmail does not detect if the log-
file is rotated, the logfile is only opened once when fetch-
mail starts. You need to restart fetchmail after rotating
the logfile and before compressing it (if applicable).
The --syslog option (keyword: set syslog) allows you to re-
direct status and error messages emitted to the syslog(3)
system daemon if available. Messages are logged with an id
of fetchmail, the facility LOG_MAIL, and priorities LOG_ERR,
LOG_ALERT or LOG_INFO. This option is intended for logging
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fetchmail reference manual fetchmail(1)
status and error messages which indicate the status of the
daemon and the results while fetching mail from the
server(s). Error messages for command line options and
parsing the .fetchmailrc file are still written to stderr,
or to the specified log file. The --nosyslog option turns
off use of syslog(3), assuming it's turned on in the
~/.fetchmailrc file.
The -N or --nodetach option suppresses backgrounding and
detachment of the daemon process from its control terminal.
This is useful for debugging or when fetchmail runs as the
child of a supervisor process such as init(8) or Gerrit
Pape's runit(8). Note that this also causes the logfile
option to be ignored (though perhaps it shouldn't).
Note that while running in daemon mode polling a POP2 or
IMAP2bis server, transient errors (such as DNS failures or
sendmail delivery refusals) may force the fetchall option on
for the duration of the next polling cycle. This is a
robustness feature. It means that if a message is fetched
(and thus marked seen by the mailserver) but not delivered
locally due to some transient error, it will be re-fetched
during the next poll cycle. (The IMAP logic doesn't delete
messages until they're delivered, so this problem does not
arise.)
If you touch or change the ~/.fetchmailrc file while fetch-
mail is running in daemon mode, this will be detected at the
beginning of the next poll cycle. When a changed ~/.fetch-
mailrc is detected, fetchmail rereads it and restarts from
scratch (using exec(2); no state information is retained in
the new instance). Note that if fetchmail needs to query
for passwords, of that if you break the ~/.fetchmailrc
file's syntax, the new instance will softly and silently
vanish away on startup.
ADMINISTRATIVE OPTIONS
The --postmaster <name> option (keyword: set postmaster)
specifies the last-resort username to which multidrop mail
is to be forwarded if no matching local recipient can be
found. It is also used as destination of undeliverable mail
if the 'bouncemail' global option is off and additionally
for spam-blocked mail if the 'bouncemail' global option is
off and the 'spambounce' global option is on. This option
defaults to the user who invoked fetchmail. If the invoking
user is root, then the default of this option is the user
'postmaster'. Setting postmaster to the empty string causes
such mail as described above to be discarded - this however
is usually a bad idea. See also the description of the
'FETCHMAILUSER' environment variable in the ENVIRONMENT sec-
tion below.
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The --nobounce behaves like the "set no bouncemail" global
option, which see.
The --invisible option (keyword: set invisible) tries to
make fetchmail invisible. Normally, fetchmail behaves like
any other MTA would -- it generates a Received header into
each message describing its place in the chain of transmis-
sion, and tells the MTA it forwards to that the mail came
from the machine fetchmail itself is running on. If the
invisible option is on, the Received header is suppressed
and fetchmail tries to spoof the MTA it forwards to into
thinking it came directly from the mailserver host.
The --showdots option (keyword: set showdots) forces fetch-
mail to show progress dots even if the output goes to a file
or fetchmail is not in verbose mode. Fetchmail shows the
dots by default when run in --verbose mode and output goes
to console. This option is ignored in --silent mode.
By specifying the --tracepolls option, you can ask fetchmail
to add information to the Received header on the form
"polling {label} account {user}", where {label} is the
account label (from the specified rcfile, normally ~/.fetch-
mailrc) and {user} is the username which is used to log on
to the mail server. This header can be used to make filter-
ing email where no useful header information is available
and you want mail from different accounts sorted into dif-
ferent mailboxes (this could, for example, occur if you have
an account on the same server running a mailing list, and
are subscribed to the list using that account). The default
is not adding any such header. In .fetchmailrc, this is
called 'tracepolls'.
RETRIEVAL FAILURE MODES
The protocols fetchmail uses to talk to mailservers are next
to bulletproof. In normal operation forwarding to port 25,
no message is ever deleted (or even marked for deletion) on
the host until the SMTP listener on the client side has
acknowledged to fetchmail that the message has been either
accepted for delivery or rejected due to a spam block.
When forwarding to an MDA, however, there is more possibil-
ity of error. Some MDAs are 'safe' and reliably return a
nonzero status on any delivery error, even one due to tempo-
rary resource limits. The maildrop(1) program is like this;
so are most programs designed as mail transport agents, such
as sendmail(1), including the sendmail wrapper of Postfix
and exim(1). These programs give back a reliable positive
acknowledgement and can be used with the mda option with no
risk of mail loss. Unsafe MDAs, though, may return 0 even
on delivery failure. If this happens, you will lose mail.
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The normal mode of fetchmail is to try to download only
'new' messages, leaving untouched (and undeleted) messages
you have already read directly on the server (or fetched
with a previous fetchmail --keep). But you may find that
messages you've already read on the server are being fetched
(and deleted) even when you don't specify --all. There are
several reasons this can happen.
One could be that you're using POP2. The POP2 protocol
includes no representation of 'new' or 'old' state in mes-
sages, so fetchmail must treat all messages as new all the
time. But POP2 is obsolete, so this is unlikely.
A potential POP3 problem might be servers that insert mes-
sages in the middle of mailboxes (some VMS implementations
of mail are rumored to do this). The fetchmail code assumes
that new messages are appended to the end of the mailbox;
when this is not true it may treat some old messages as new
and vice versa. Using UIDL whilst setting fastuidl 0 might
fix this, otherwise, consider switching to IMAP.
Yet another POP3 problem is that if they can't make temp-
files in the user's home directory, some POP3 servers will
hand back an undocumented response that causes fetchmail to
spuriously report "No mail".
The IMAP code uses the presence or absence of the server
flag \Seen to decide whether or not a message is new. This
isn't the right thing to do, fetchmail should check the UID-
VALIDITY and use UID, but it doesn't do that yet. Under
Unix, it counts on your IMAP server to notice the BSD-style
Status flags set by mail user agents and set the \Seen flag
from them when appropriate. All Unix IMAP servers we know
of do this, though it's not specified by the IMAP RFCs. If
you ever trip over a server that doesn't, the symptom will
be that messages you have already read on your host will
look new to the server. In this (unlikely) case, only mes-
sages you fetched with fetchmail --keep will be both
undeleted and marked old.
In ETRN and ODMR modes, fetchmail does not actually retrieve
messages; instead, it asks the server's SMTP listener to
start a queue flush to the client via SMTP. Therefore it
sends only undelivered messages.
SPAM FILTERING
Many SMTP listeners allow administrators to set up 'spam
filters' that block unsolicited email from specified
domains. A MAIL FROM or DATA line that triggers this fea-
ture will elicit an SMTP response which (unfortunately)
varies according to the listener.
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Newer versions of sendmail return an error code of 571.
According to RFC2821, the correct thing to return in this
situation is 550 "Requested action not taken: mailbox
unavailable" (the draft adds "[E.g., mailbox not found, no
access, or command rejected for policy reasons].").
Older versions of the exim MTA return 501 "Syntax error in
parameters or arguments".
The postfix MTA runs 554 as an antispam response.
Zmailer may reject code with a 500 response (followed by an
enhanced status code that contains more information).
Return codes which fetchmail treats as antispam responses
and discards the message can be set with the 'antispam'
option. This is one of the only three circumstance under
which fetchmail ever discards mail (the others are the 552
and 553 errors described below, and the suppression of mul-
tidropped messages with a message-ID already seen).
If fetchmail is fetching from an IMAP server, the antispam
response will be detected and the message rejected immedi-
ately after the headers have been fetched, without reading
the message body. Thus, you won't pay for downloading spam
message bodies.
By default, the list of antispam responses is empty.
If the spambounce global option is on, mail that is spam-
blocked triggers an RFC1892/RFC1894 bounce message informing
the originator that we do not accept mail from it. See also
BUGS.
SMTP/ESMTP ERROR HANDLING
Besides the spam-blocking described above, fetchmail takes
special actions on the following SMTP/ESMTP error responses
452 (insufficient system storage)
Leave the message in the server mailbox for later
retrieval.
552 (message exceeds fixed maximum message size)
Delete the message from the server. Send bounce-mail
to the originator.
553 (invalid sending domain)
Delete the message from the server. Don't even try to
send bounce-mail to the originator.
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Other errors trigger bounce mail back to the originator. See
also BUGS.
THE RUN CONTROL FILE
The preferred way to set up fetchmail is to write a .fetch-
mailrc file in your home directory (you may do this
directly, with a text editor, or indirectly via fetchmail-
conf). When there is a conflict between the command-line
arguments and the arguments in this file, the command-line
arguments take precedence.
To protect the security of your passwords, your ~/.fetch-
mailrc may not normally have more than 0700 (u=rwx,g=,o=)
permissions; fetchmail will complain and exit otherwise
(this check is suppressed when --version is on).
You may read the .fetchmailrc file as a list of commands to
be executed when fetchmail is called with no arguments.
Run Control Syntax
Comments begin with a '#' and extend through the end of the
line. Otherwise the file consists of a series of server
entries or global option statements in a free-format, token-
oriented syntax.
There are four kinds of tokens: grammar keywords, numbers
(i.e. decimal digit sequences), unquoted strings, and quoted
strings. A quoted string is bounded by double quotes and
may contain whitespace (and quoted digits are treated as a
string). Note that quoted strings will also contain line
feed characters if they run across two or more lines, unless
you use a backslash to join lines (see below). An unquoted
string is any whitespace-delimited token that is neither
numeric, string quoted nor contains the special characters
',', ';', ':', or '='.
Any amount of whitespace separates tokens in server entries,
but is otherwise ignored. You may use backslash escape
sequences (\n for LF, \t for HT, \b for BS, \r for CR, \nnn
for decimal (where nnn cannot start with a 0), \0ooo for
octal, and \xhh for hex) to embed non-printable characters
or string delimiters in strings. In quoted strings, a back-
slash at the very end of a line will cause the backslash
itself and the line feed (LF or NL, new line) character to
be ignored, so that you can wrap long strings. Without the
backslash at the line end, the line feed character would
become part of the string.
Warning: while these resemble C-style escape sequences, they
are not the same. fetchmail only supports these eight
styles. C supports more escape sequences that consist of
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fetchmail reference manual fetchmail(1)
backslash (\) and a single character, but does not support
decimal codes and does not require the leading 0 in octal
notation. Example: fetchmail interprets \233 the same as
\xE9 (Latin small letter e with acute), where C would inter-
pret \233 as octal 0233 = \x9B (CSI, control sequence intro-
ducer).
Each server entry consists of one of the keywords 'poll' or
'skip', followed by a server name, followed by server
options, followed by any number of user (or username)
descriptions, followed by user options. Note: the most com-
mon cause of syntax errors is mixing up user and server
options or putting user options before the user descrip-
tions.
For backward compatibility, the word 'server' is a synonym
for 'poll'.
You can use the noise keywords 'and', 'with', 'has',
'wants', and 'options' anywhere in an entry to make it
resemble English. They're ignored, but but can make entries
much easier to read at a glance. The punctuation characters
':', ';' and ',' are also ignored.
Poll vs. Skip
The 'poll' verb tells fetchmail to query this host when it
is run with no arguments. The 'skip' verb tells fetchmail
not to poll this host unless it is explicitly named on the
command line. (The 'skip' verb allows you to experiment
with test entries safely, or easily disable entries for
hosts that are temporarily down.)
Keyword/Option Summary
Here are the legal options. Keyword suffixes enclosed in
square brackets are optional. Those corresponding to short
command-line options are followed by '-' and the appropriate
option letter. If option is only relevant to a single mode
of operation, it is noted as 's' or 'm' for singledrop- or
multidrop-mode, respectively.
Here are the legal global options:
Keyword Opt Mode Function
--------------------------------------------------------------------
set daemon -d Set a background poll interval in
seconds.
set postmaster Give the name of the last-resort
mail recipient (default: user run-
ning fetchmail, "postmaster" if
run by the root user)
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set bouncemail Direct error mail to the sender
(default)
set no bouncemail Direct error mail to the local
postmaster (as per the 'postmas-
ter' global option above).
set no spambounce Do not bounce spam-blocked mail
(default).
set spambounce Bounce blocked spam-blocked mail
(as per the 'antispam' user
option) back to the destination as
indicated by the 'bouncemail'
global option. Warning: Do not
use this to bounce spam back to
the sender - most spam is sent
with false sender address and thus
this option hurts innocent
bystanders.
set no softbounce Delete permanently undeliverable
mail. It is recommended to use
this option if the configuration
has been thoroughly tested.
set softbounce Keep permanently undeliverable
mail as though a temporary error
had occurred (default).
set logfile -L Name of a file to append error and
status messages to.
set idfile -i Name of the file to store UID
lists in.
set syslog Do error logging through sys-
log(3).
set no syslog Turn off error logging through
syslog(3). (default)
set properties String value that is ignored by
fetchmail (may be used by exten-
sion scripts).
Here are the legal server options:
Keyword Opt Mode Function
-----------------------------------------------------------------
via Specify DNS name of mailserver,
overriding poll name
proto[col] -p Specify protocol (case insensi-
tive): POP2, POP3, IMAP, APOP,
KPOP
local[domains] m Specify domain(s) to be regarded
as local
port Specify TCP/IP service port (obso-
lete, use 'service' instead).
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service -P Specify service name (a numeric
value is also allowed and consid-
ered a TCP/IP port number).
auth[enticate] Set authentication type (default
'any')
timeout -t Server inactivity timeout in sec-
onds (default 300)
envelope -E m Specify envelope-address header
name
no envelope m Disable looking for envelope
address
qvirtual -Q m Qmail virtual domain prefix to
remove from user name
aka m Specify alternate DNS names of
mailserver
interface -I specify IP interface(s) that must
be up for server poll to take
place
monitor -M Specify IP address to monitor for
activity
plugin Specify command through which to
make server connections.
plugout Specify command through which to
make listener connections.
dns m Enable DNS lookup for multidrop
(default)
no dns m Disable DNS lookup for multidrop
checkalias m Do comparison by IP address for
multidrop
no checkalias m Do comparison by name for mul-
tidrop (default)
uidl -U Force POP3 to use client-side
UIDLs (recommended)
no uidl Turn off POP3 use of client-side
UIDLs (default)
interval Only check this site every N poll
cycles; N is a numeric argument.
tracepolls Add poll tracing information to
the Received header
principal Set Kerberos principal (only use-
ful with IMAP and kerberos)
esmtpname Set name for RFC2554 authentica-
tion to the ESMTP server.
esmtppassword Set password for RFC2554 authenti-
cation to the ESMTP server.
bad-header How to treat messages with a bad
header. Can be reject (default) or
accept.
Here are the legal user descriptions and options:
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Keyword Opt Mode Function
-------------------------------------------------------------------
user[name] -u This is the user description and
must come first after server
description and after possible
server options, and before user
options.
It sets the remote user name if by
itself or followed by 'there', or
the local user name if followed by
'here'.
is Connect local and remote user
names
to Connect local and remote user
names
pass[word] Specify remote account password
ssl Connect to server over the speci-
fied base protocol using SSL
encryption
sslcert Specify file for client side pub-
lic SSL certificate
sslcertfile Specify file with trusted CA cer-
tificates
sslcertpath Specify c_rehash-ed directory with
trusted CA certificates.
sslkey Specify file for client side pri-
vate SSL key
sslproto Force ssl protocol for connection
folder -r Specify remote folder to query
smtphost -S Specify smtp host(s) to forward to
fetchdomains m Specify domains for which mail
should be fetched
smtpaddress -D Specify the domain to be put in
RCPT TO lines
smtpname Specify the user and domain to be
put in RCPT TO lines
antispam -Z Specify what SMTP returns are
interpreted as spam-policy blocks
mda -m Specify MDA for local delivery
bsmtp -o Specify BSMTP batch file to append
to
preconnect Command to be executed before each
connection
postconnect Command to be executed after each
connection
keep -k Don't delete seen messages from
server (for POP3, uidl is recom-
mended)
flush -F Flush all seen messages before
querying (DANGEROUS)
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fetchmail reference manual fetchmail(1)
limitflush Flush all oversized messages
before querying
fetchall -a Fetch all messages whether seen or
not
rewrite Rewrite destination addresses for
reply (default)
stripcr Strip carriage returns from ends
of lines
forcecr Force carriage returns at ends of
lines
pass8bits Force BODY=8BITMIME to ESMTP lis-
tener
dropstatus Strip Status and X-Mozilla-Status
lines out of incoming mail
dropdelivered Strip Delivered-To lines out of
incoming mail
mimedecode Convert quoted-printable to 8-bit
in MIME messages
idle Idle waiting for new messages
after each poll (IMAP only)
no keep -K Delete seen messages from server
(default)
no flush Don't flush all seen messages
before querying (default)
no fetchall Retrieve only new messages
(default)
no rewrite Don't rewrite headers
no stripcr Don't strip carriage returns
(default)
no forcecr Don't force carriage returns at
EOL (default)
no pass8bits Don't force BODY=8BITMIME to ESMTP
listener (default)
no dropstatus Don't drop Status headers
(default)
no dropdelivered Don't drop Delivered-To headers
(default)
no mimedecode Don't convert quoted-printable to
8-bit in MIME messages (default)
no idle Don't idle waiting for new mes-
sages after each poll (IMAP only)
limit -l Set message size limit
warnings -w Set message size warning interval
batchlimit -b Max # messages to forward in sin-
gle connect
fetchlimit -B Max # messages to fetch in single
connect
fetchsizelimit Max # message sizes to fetch in
single transaction
fastuidl Use binary search for first unseen
message (POP3 only)
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expunge -e Perform an expunge on every #th
message (IMAP and POP3 only)
properties String value is ignored by fetch-
mail (may be used by extension
scripts)
All user options must begin with a user description (user or
username option) and follow all server descriptions and
options.
In the .fetchmailrc file, the 'envelope' string argument may
be preceded by a whitespace-separated number. This number,
if specified, is the number of such headers to skip over
(that is, an argument of 1 selects the second header of the
given type). This is sometime useful for ignoring bogus
envelope headers created by an ISP's local delivery agent or
internal forwards (through mail inspection systems, for
instance).
Keywords Not Corresponding To Option Switches
The 'folder' and 'smtphost' options (unlike their command-
line equivalents) can take a space- or comma-separated list
of names following them.
All options correspond to the obvious command-line argu-
ments, except the following: 'via', 'interval', 'aka', 'is',
'to', 'dns'/'no dns', 'checkalias'/'no checkalias', 'pass-
word', 'preconnect', 'postconnect', 'localdomains',
'stripcr'/'no stripcr', 'forcecr'/'no forcecr',
'pass8bits'/'no pass8bits' 'dropstatus/no dropstatus',
'dropdelivered/no dropdelivered', 'mimedecode/no mimede-
code', 'no idle', and 'no envelope'.
The 'via' option is for if you want to have more than one
configuration pointing at the same site. If it is present,
the string argument will be taken as the actual DNS name of
the mailserver host to query. This will override the argu-
ment of poll, which can then simply be a distinct label for
the configuration (e.g. what you would give on the command
line to explicitly query this host).
The 'interval' option (which takes a numeric argument)
allows you to poll a server less frequently than the basic
poll interval. If you say 'interval N' the server this
option is attached to will only be queried every N poll
intervals.
Singledrop vs. Multidrop options
Please ensure you read the section titled THE USE AND ABUSE
OF MULTIDROP MAILBOXES if you intend to use multidrop mode.
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The 'is' or 'to' keywords associate the following local
(client) name(s) (or server-name to client-name mappings
separated by =) with the mailserver user name in the entry.
If an is/to list has '*' as its last name, unrecognized
names are simply passed through. Note that until fetchmail
version 6.3.4 inclusively, these lists could only contain
local parts of user names (fetchmail would only look at the
part before the @ sign). fetchmail versions 6.3.5 and newer
support full addresses on the left hand side of these map-
pings, and they take precedence over any 'localdomains',
'aka', 'via' or similar mappings.
A single local name can be used to support redirecting your
mail when your username on the client machine is different
from your name on the mailserver. When there is only a sin-
gle local name, mail is forwarded to that local username
regardless of the message's Received, To, Cc, and Bcc head-
ers. In this case, fetchmail never does DNS lookups.
When there is more than one local name (or name mapping),
fetchmail looks at the envelope header, if configured, and
otherwise at the Received, To, Cc, and Bcc headers of
retrieved mail (this is 'multidrop mode'). It looks for
addresses with hostname parts that match your poll name or
your 'via', 'aka' or 'localdomains' options, and usually
also for hostname parts which DNS tells it are aliases of
the mailserver. See the discussion of 'dns', 'checkalias',
'localdomains', and 'aka' for details on how matching
addresses are handled.
If fetchmail cannot match any mailserver usernames or local-
domain addresses, the mail will be bounced. Normally it
will be bounced to the sender, but if the 'bouncemail'
global option is off, the mail will go to the local postmas-
ter instead. (see the 'postmaster' global option). See also
BUGS.
The 'dns' option (normally on) controls the way addresses
from multidrop mailboxes are checked. On, it enables logic
to check each host address that does not match an 'aka' or
'localdomains' declaration by looking it up with DNS. When
a mailserver username is recognized attached to a matching
hostname part, its local mapping is added to the list of
local recipients.
The 'checkalias' option (normally off) extends the lookups
performed by the 'dns' keyword in multidrop mode, providing
a way to cope with remote MTAs that identify themselves
using their canonical name, while they're polled using an
alias. When such a server is polled, checks to extract the
envelope address fail, and fetchmail reverts to delivery
using the To/Cc/Bcc headers (See below 'Header vs. Envelope
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fetchmail reference manual fetchmail(1)
addresses'). Specifying this option instructs fetchmail to
retrieve all the IP addresses associated with both the poll
name and the name used by the remote MTA and to do a compar-
ison of the IP addresses. This comes in handy in situations
where the remote server undergoes frequent canonical name
changes, that would otherwise require modifications to the
rcfile. 'checkalias' has no effect if 'no dns' is specified
in the rcfile.
The 'aka' option is for use with multidrop mailboxes. It
allows you to pre-declare a list of DNS aliases for a
server. This is an optimization hack that allows you to
trade space for speed. When fetchmail, while processing a
multidrop mailbox, grovels through message headers looking
for names of the mailserver, pre-declaring common ones can
save it from having to do DNS lookups. Note: the names you
give as arguments to 'aka' are matched as suffixes -- if you
specify (say) 'aka netaxs.com', this will match not just a
hostname netaxs.com, but any hostname that ends with
'.netaxs.com'; such as (say) pop3.netaxs.com and
mail.netaxs.com.
The 'localdomains' option allows you to declare a list of
domains which fetchmail should consider local. When fetch-
mail is parsing address lines in multidrop modes, and a
trailing segment of a host name matches a declared local
domain, that address is passed through to the listener or
MDA unaltered (local-name mappings are not applied).
If you are using 'localdomains', you may also need to spec-
ify 'no envelope', which disables fetchmail's normal attempt
to deduce an envelope address from the Received line or X-
Envelope-To header or whatever header has been previously
set by 'envelope'. If you set 'no envelope' in the defaults
entry it is possible to undo that in individual entries by
using 'envelope <string>'. As a special case, 'envelope
"Received"' restores the default parsing of Received lines.
The password option requires a string argument, which is the
password to be used with the entry's server.
The 'preconnect' keyword allows you to specify a shell com-
mand to be executed just before each time fetchmail estab-
lishes a mailserver connection. This may be useful if you
are attempting to set up secure POP connections with the aid
of ssh(1). If the command returns a nonzero status, the
poll of that mailserver will be aborted.
Similarly, the 'postconnect' keyword similarly allows you to
specify a shell command to be executed just after each time
a mailserver connection is taken down.
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The 'forcecr' option controls whether lines terminated by LF
only are given CRLF termination before forwarding. Strictly
speaking RFC821 requires this, but few MTAs enforce the
requirement it so this option is normally off (only one such
MTA, qmail, is in significant use at time of writing).
The 'stripcr' option controls whether carriage returns are
stripped out of retrieved mail before it is forwarded. It
is normally not necessary to set this, because it defaults
to 'on' (CR stripping enabled) when there is an MDA declared
but 'off' (CR stripping disabled) when forwarding is via
SMTP. If 'stripcr' and 'forcecr' are both on, 'stripcr'
will override.
The 'pass8bits' option exists to cope with Microsoft mail
programs that stupidly slap a "Content-Transfer-Encoding:
7bit" on everything. With this option off (the default) and
such a header present, fetchmail declares BODY=7BIT to an
ESMTP-capable listener; this causes problems for messages
actually using 8-bit ISO or KOI-8 character sets, which will
be garbled by having the high bits of all characters
stripped. If 'pass8bits' is on, fetchmail is forced to
declare BODY=8BITMIME to any ESMTP-capable listener. If the
listener is 8-bit-clean (as all the major ones now are) the
right thing will probably result.
The 'dropstatus' option controls whether nonempty Status and
X-Mozilla-Status lines are retained in fetched mail (the
default) or discarded. Retaining them allows your MUA to
see what messages (if any) were marked seen on the server.
On the other hand, it can confuse some new-mail notifiers,
which assume that anything with a Status line in it has been
seen. (Note: the empty Status lines inserted by some buggy
POP servers are unconditionally discarded.)
The 'dropdelivered' option controls whether Delivered-To
headers will be kept in fetched mail (the default) or dis-
carded. These headers are added by Qmail and Postfix
mailservers in order to avoid mail loops but may get in your
way if you try to "mirror" a mailserver within the same
domain. Use with caution.
The 'mimedecode' option controls whether MIME messages using
the quoted-printable encoding are automatically converted
into pure 8-bit data. If you are delivering mail to an
ESMTP-capable, 8-bit-clean listener (that includes all of
the major MTAs like sendmail), then this will automatically
convert quoted-printable message headers and data into 8-bit
data, making it easier to understand when reading mail. If
your e-mail programs know how to deal with MIME messages,
then this option is not needed. The mimedecode option is
off by default, because doing RFC2047 conversion on headers
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throws away character-set information and can lead to bad
results if the encoding of the headers differs from the body
encoding.
The 'idle' option is intended to be used with IMAP servers
supporting the RFC2177 IDLE command extension, but does not
strictly require it. If it is enabled, and fetchmail
detects that IDLE is supported, an IDLE will be issued at
the end of each poll. This will tell the IMAP server to
hold the connection open and notify the client when new mail
is available. If IDLE is not supported, fetchmail will sim-
ulate it by periodically issuing NOOP. If you need to poll a
link frequently, IDLE can save bandwidth by eliminating
TCP/IP connects and LOGIN/LOGOUT sequences. On the other
hand, an IDLE connection will eat almost all of your fetch-
mail's time, because it will never drop the connection and
allow other polls to occur unless the server times out the
IDLE. It also doesn't work with multiple folders; only the
first folder will ever be polled.
The 'properties' option is an extension mechanism. It takes
a string argument, which is ignored by fetchmail itself.
The string argument may be used to store configuration
information for scripts which require it. In particular,
the output of '--configdump' option will make properties
associated with a user entry readily available to a Python
script.
Miscellaneous Run Control Options
The words 'here' and 'there' have useful English-like sig-
nificance. Normally 'user eric is esr' would mean that mail
for the remote user 'eric' is to be delivered to 'esr', but
you can make this clearer by saying 'user eric there is esr
here', or reverse it by saying 'user esr here is eric there'
Legal protocol identifiers for use with the 'protocol' key-
word are:
auto (or AUTO) (legacy, to be removed from future release)
pop2 (or POP2) (legacy, to be removed from future release)
pop3 (or POP3)
sdps (or SDPS)
imap (or IMAP)
apop (or APOP)
kpop (or KPOP)
Legal authentication types are 'any', 'password', 'ker-
beros', 'kerberos_v4', 'kerberos_v5' and 'gssapi',
'cram-md5', 'otp', 'msn' (only for POP3), 'ntlm', 'ssh',
'external' (only IMAP). The 'password' type specifies
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authentication by normal transmission of a password (the
password may be plain text or subject to protocol-specific
encryption as in CRAM-MD5); 'kerberos' tells fetchmail to
try to get a Kerberos ticket at the start of each query
instead, and send an arbitrary string as the password; and
'gssapi' tells fetchmail to use GSSAPI authentication. See
the description of the 'auth' keyword for more.
Specifying 'kpop' sets POP3 protocol over port 1109 with
Kerberos V4 authentication. These defaults may be overrid-
den by later options.
There are some global option statements: 'set logfile' fol-
lowed by a string sets the same global specified by --log-
file. A command-line --logfile option will override this.
Note that --logfile is only effective if fetchmail detaches
itself from the terminal and the logfile already exists
before fetchmail is run, and it overrides --syslog in this
case. Also, 'set daemon' sets the poll interval as --daemon
does. This can be overridden by a command-line --daemon
option; in particular --daemon 0 can be used to force fore-
ground operation. The 'set postmaster' statement sets the
address to which multidrop mail defaults if there are no
local matches. Finally, 'set syslog' sends log messages to
syslogd(8).
DEBUGGING FETCHMAIL
Fetchmail crashing
There are various ways in that fetchmail may "crash", i. e.
stop operation suddenly and unexpectedly. A "crash" usually
refers to an error condition that the software did not han-
dle by itself. A well-known failure mode is the "segmenta-
tion fault" or "signal 11" or "SIGSEGV" or just "segfault"
for short. These can be caused by hardware or by software
problems. Software-induced segfaults can usually be repro-
duced easily and in the same place, whereas hardware-induced
segfaults can go away if the computer is rebooted, or pow-
ered off for a few hours, and can happen in random locations
even if you use the software the same way.
For solving hardware-induced segfaults, find the faulty com-
ponent and repair or replace it. may help you with details.
For solving software-induced segfaults, the developers may
need a "stack backtrace".
Enabling fetchmail core dumps
By default, fetchmail suppresses core dumps as these might
contain passwords and other sensitive information. For
debugging fetchmail crashes, obtaining a "stack backtrace"
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from a core dump is often the quickest way to solve the
problem, and when posting your problem on a mailing list,
the developers may ask you for a "backtrace".
1. To get useful backtraces, fetchmail needs to be installed
without getting stripped of its compilation symbols. Unfor-
tunately, most binary packages that are installed are
stripped, and core files from symbol-stripped programs are
worthless. So you may need to recompile fetchmail. On many
systems, you can type
file `which fetchmail`
to find out if fetchmail was symbol-stripped or not. If
yours was unstripped, fine, proceed, if it was stripped, you
need to recompile the source code first. You do not usually
need to install fetchmail in order to debug it.
2. The shell environment that starts fetchmail needs to
enable core dumps. The key is the "maximum core (file) size"
that can usually be configured with a tool named "limit" or
"ulimit". See the documentation for your shell for details.
In the popular bash shell, "ulimit -Sc unlimited" will allow
the core dump.
3. You need to tell fetchmail, too, to allow core dumps. To
do this, run fetchmail with the -d0 -v options. It is often
easier to also add --nosyslog -N as well.
Finally, you need to reproduce the crash. You can just start
fetchmail from the directory where you compiled it by typing
./fetchmail, so the complete command line will start with
./fetchmail -Nvd0 --nosyslog and perhaps list your other
options.
After the crash, run your debugger to obtain the core dump.
The debugger will often be GNU GDB, you can then type
(adjust paths as necessary) gdb ./fetchmail fetchmail.core
and then, after GDB has started up and read all its files,
type backtrace full, save the output (copy & paste will do,
the backtrace will be read by a human) and then type quit to
leave gdb. Note: on some systems, the core files have dif-
ferent names, they might contain a number instead of the
program name, or number and name, but it will usually have
"core" as part of their name.
INTERACTION WITH RFC 822
When trying to determine the originating address of a mes-
sage, fetchmail looks through headers in the following
order:
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Return-Path:
Resent-Sender: (ignored if it doesn't contain an @ or !)
Sender: (ignored if it doesn't contain an @ or !)
Resent-From:
From:
Reply-To:
Apparently-From:
The originating address is used for logging, and to set the
MAIL FROM address when forwarding to SMTP. This order is
intended to cope gracefully with receiving mailing list mes-
sages in multidrop mode. The intent is that if a local
address doesn't exist, the bounce message won't be returned
blindly to the author or to the list itself, but rather to
the list manager (which is less annoying).
In multidrop mode, destination headers are processed as fol-
lows: First, fetchmail looks for the header specified by the
'envelope' option in order to determine the local recipient
address. If the mail is addressed to more than one recipi-
ent, the Received line won't contain any information regard-
ing recipient addresses.
Then fetchmail looks for the Resent-To:, Resent-Cc:, and
Resent-Bcc: lines. If they exist, they should contain the
final recipients and have precedence over their To:/Cc:/Bcc:
counterparts. If the Resent-* lines don't exist, the To:,
Cc:, Bcc: and Apparently-To: lines are looked for. (The
presence of a Resent-To: is taken to imply that the person
referred by the To: address has already received the origi-
nal copy of the mail.)
CONFIGURATION EXAMPLES
Note that although there are password declarations in a good
many of the examples below, this is mainly for illustrative
purposes. We recommend stashing account/password pairs in
your $HOME/.netrc file, where they can be used not just by
fetchmail but by ftp(1) and other programs.
The basic format is:
poll SERVERNAME protocol PROTOCOL username NAME pass-
word PASSWORD
Example:
poll pop.provider.net protocol pop3 username "jsmith" password "secret1"
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Or, using some abbreviations:
poll pop.provider.net proto pop3 user "jsmith" password "secret1"
Multiple servers may be listed:
poll pop.provider.net proto pop3 user "jsmith" pass "secret1"
poll other.provider.net proto pop2 user "John.Smith" pass "My^Hat"
Here's the same version with more whitespace and some noise
words:
poll pop.provider.net proto pop3
user "jsmith", with password secret1, is "jsmith" here;
poll other.provider.net proto pop2:
user "John.Smith", with password "My^Hat", is "John.Smith" here;
If you need to include whitespace in a parameter string or
start the latter with a number, enclose the string in double
quotes. Thus:
poll mail.provider.net with proto pop3:
user "jsmith" there has password "4u but u can't krak this"
is jws here and wants mda "/bin/mail"
You may have an initial server description headed by the
keyword 'defaults' instead of 'poll' followed by a name.
Such a record is interpreted as defaults for all queries to
use. It may be overwritten by individual server descrip-
tions. So, you could write:
defaults proto pop3
user "jsmith"
poll pop.provider.net
pass "secret1"
poll mail.provider.net
user "jjsmith" there has password "secret2"
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It's possible to specify more than one user per server. The
'user' keyword leads off a user description, and every user
specification in a multi-user entry must include it. Here's
an example:
poll pop.provider.net proto pop3 port 3111
user "jsmith" with pass "secret1" is "smith" here
user jones with pass "secret2" is "jjones" here keep
This associates the local username 'smith' with the
pop.provider.net username 'jsmith' and the local username
'jjones' with the pop.provider.net username 'jones'. Mail
for 'jones' is kept on the server after download.
Here's what a simple retrieval configuration for a multidrop
mailbox looks like:
poll pop.provider.net:
user maildrop with pass secret1 to golux 'hurkle'='happy' snark here
This says that the mailbox of account 'maildrop' on the
server is a multidrop box, and that messages in it should be
parsed for the server user names 'golux', 'hurkle', and
'snark'. It further specifies that 'golux' and 'snark' have
the same name on the client as on the server, but mail for
server user 'hurkle' should be delivered to client user
'happy'.
Note that fetchmail, until version 6.3.4, did NOT allow full
user@domain specifications here, these would never match.
Fetchmail 6.3.5 and newer support user@domain specifications
on the left-hand side of a user mapping.
Here's an example of another kind of multidrop connection:
poll pop.provider.net localdomains loonytoons.org toons.org
envelope X-Envelope-To
user maildrop with pass secret1 to * here
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This also says that the mailbox of account 'maildrop' on the
server is a multidrop box. It tells fetchmail that any
address in the loonytoons.org or toons.org domains (includ-
ing sub-domain addresses like 'joe@daffy.loonytoons.org')
should be passed through to the local SMTP listener without
modification. Be careful of mail loops if you do this!
Here's an example configuration using ssh and the plugin
option. The queries are made directly on the stdin and std-
out of imapd via ssh. Note that in this setup, IMAP authen-
tication can be skipped.
poll mailhost.net with proto imap:
plugin "ssh %h /usr/sbin/imapd" auth ssh;
user esr is esr here
THE USE AND ABUSE OF MULTIDROP
Use the multiple-local-recipients feature with caution -- it
can bite. All multidrop features are ineffective in ETRN
and ODMR modes.
Also, note that in multidrop mode duplicate mails are sup-
pressed. A piece of mail is considered duplicate if it has
the same message-ID as the message immediately preceding and
more than one addressee. Such runs of messages may be gen-
erated when copies of a message addressed to multiple users
are delivered to a multidrop box.
Header vs. Envelope addresses
The fundamental problem is that by having your mailserver
toss several peoples' mail in a single maildrop box, you may
have thrown away potentially vital information about who
each piece of mail was actually addressed to (the 'envelope
address', as opposed to the header addresses in the RFC822
To/Cc headers - the Bcc is not available at the receiving
end). This 'envelope address' is the address you need in
order to reroute mail properly.
Sometimes fetchmail can deduce the envelope address. If the
mailserver MTA is sendmail and the item of mail had just one
recipient, the MTA will have written a 'by/for' clause that
gives the envelope addressee into its Received header. But
this doesn't work reliably for other MTAs, nor if there is
more than one recipient. By default, fetchmail looks for
envelope addresses in these lines; you can restore this
default with -E "Received" or 'envelope Received'.
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As a better alternative, some SMTP listeners and/or mail
servers insert a header in each message containing a copy of
the envelope addresses. This header (when it exists) is
often 'X-Original-To', 'Delivered-To' or 'X-Envelope-To'.
Fetchmail's assumption about this can be changed with the -E
or 'envelope' option. Note that writing an envelope header
of this kind exposes the names of recipients (including
blind-copy recipients) to all receivers of the messages, so
the upstream must store one copy of the message per recipi-
ent to avoid becoming a privacy problem.
Postfix, since version 2.0, writes an X-Original-To: header
which contains a copy of the envelope as it was received.
Qmail and Postfix generally write a 'Delivered-To' header
upon delivering the message to the mail spool and use it to
avoid mail loops. Qmail virtual domains however will prefix
the user name with a string that normally matches the user's
domain. To remove this prefix you can use the -Q or 'qvir-
tual' option.
Sometimes, unfortunately, neither of these methods works.
That is the point when you should contact your ISP and ask
them to provide such an envelope header, and you should not
use multidrop in this situation. When they all fail, fetch-
mail must fall back on the contents of To/Cc headers (Bcc
headers are not available - see below) to try to determine
recipient addressees -- and these are unreliable. In par-
ticular, mailing-list software often ships mail with only
the list broadcast address in the To header.
Note that a future version of fetchmail may remove To/Cc
parsing!
When fetchmail cannot deduce a recipient address that is
local, and the intended recipient address was anyone other
than fetchmail's invoking user, mail will get lost. This is
what makes the multidrop feature risky without proper enve-
lope information.
A related problem is that when you blind-copy a mail mes-
sage, the Bcc information is carried only as envelope
address (it's removed from the headers by the sending mail
server, so fetchmail can see it only if there is an X-Enve-
lope-To header). Thus, blind-copying to someone who gets
mail over a fetchmail multidrop link will fail unless the
the mailserver host routinely writes X-Envelope-To or an
equivalent header into messages in your maildrop.
In conclusion, mailing lists and Bcc'd mail can only work if
the server you're fetching from
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(1) stores one copy of the message per recipient in your
domain and
(2) records the envelope information in a special header
(X-Original-To, Delivered-To, X-Envelope-To).
Good Ways To Use Multidrop Mailboxes
Multiple local names can be used to administer a mailing
list from the client side of a fetchmail collection. Sup-
pose your name is 'esr', and you want to both pick up your
own mail and maintain a mailing list called (say) "fetch-
mail-friends", and you want to keep the alias list on your
client machine.
On your server, you can alias 'fetchmail-friends' to 'esr';
then, in your .fetchmailrc, declare 'to esr fetch-
mail-friends here'. Then, when mail including 'fetch-
mail-friends' as a local address gets fetched, the list name
will be appended to the list of recipients your SMTP lis-
tener sees. Therefore it will undergo alias expansion
locally. Be sure to include 'esr' in the local alias expan-
sion of fetchmail-friends, or you'll never see mail sent
only to the list. Also be sure that your listener has the
"me-too" option set (sendmail's -oXm command-line option or
OXm declaration) so your name isn't removed from alias
expansions in messages you send.
This trick is not without its problems, however. You'll
begin to see this when a message comes in that is addressed
only to a mailing list you do not have declared as a local
name. Each such message will feature an 'X-Fetchmail-Warn-
ing' header which is generated because fetchmail cannot find
a valid local name in the recipient addresses. Such mes-
sages default (as was described above) to being sent to the
local user running fetchmail, but the program has no way to
know that that's actually the right thing.
Bad Ways To Abuse Multidrop Mailboxes
Multidrop mailboxes and fetchmail serving multiple users in
daemon mode do not mix. The problem, again, is mail from
mailing lists, which typically does not have an individual
recipient address on it. Unless fetchmail can deduce an
envelope address, such mail will only go to the account run-
ning fetchmail (probably root). Also, blind-copied users
are very likely never to see their mail at all.
If you're tempted to use fetchmail to retrieve mail for mul-
tiple users from a single mail drop via POP or IMAP, think
again (and reread the section on header and envelope
addresses above). It would be smarter to just let the mail
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sit in the mailserver's queue and use fetchmail's ETRN or
ODMR modes to trigger SMTP sends periodically (of course,
this means you have to poll more frequently than the
mailserver's expiry period). If you can't arrange this, try
setting up a UUCP feed.
If you absolutely must use multidrop for this purpose, make
sure your mailserver writes an envelope-address header that
fetchmail can see. Otherwise you will lose mail and it will
come back to haunt you.
Speeding Up Multidrop Checking
Normally, when multiple users are declared fetchmail
extracts recipient addresses as described above and checks
each host part with DNS to see if it's an alias of the
mailserver. If so, the name mappings described in the "to
... here" declaration are done and the mail locally deliv-
ered.
This is a convenient but also slow method. To speed it up,
pre-declare mailserver aliases with 'aka'; these are checked
before DNS lookups are done. If you're certain your aka
list contains all DNS aliases of the mailserver (and all MX
names pointing at it - note this may change in a future ver-
sion) you can declare 'no dns' to suppress DNS lookups
entirely and only match against the aka list.
SOCKS
Support for socks4/5 is a compile time configuration option.
Once compiled in, fetchmail will always use the socks
libraries and configuration on your system, there are no
run-time switches in fetchmail - but you can still configure
SOCKS: you can specify which SOCKS configuration file is
used in the SOCKS_CONF environment variable.
For instance, if you wanted to bypass the SOCKS proxy alto-
gether and have fetchmail connect directly, you could just
pass SOCKS_CONF=/dev/null in the environment, for example
(add your usual command line options - if any - to the end
of this line):
env SOCKS_CONF=/dev/null fetchmail
EXIT CODES
To facilitate the use of fetchmail in shell scripts, an
exit status code is returned to give an indication of what
occurred during a given connection.
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fetchmail reference manual fetchmail(1)
The exit codes returned by fetchmail are as follows:
0 One or more messages were successfully retrieved (or,
if the -c option was selected, were found waiting but
not retrieved).
1 There was no mail awaiting retrieval. (There may have
been old mail still on the server but not selected for
retrieval.) If you do not want "no mail" to be an error
condition (for instance, for cron jobs), use a POSIX-
compliant shell and add
|| [ $? -eq 1 ]
to the end of the fetchmail command line, note that
this leaves 0 untouched, maps 1 to 0, and maps all
other codes to 1. See also item #C8 in the FAQ.
2 An error was encountered when attempting to open a
socket to retrieve mail. If you don't know what a
socket is, don't worry about it -- just treat this as
an 'unrecoverable error'. This error can also be
because a protocol fetchmail wants to use is not listed
in /etc/services.
3 The user authentication step failed. This usually
means that a bad user-id, password, or APOP id was
specified. Or it may mean that you tried to run fetch-
mail under circumstances where it did not have standard
input attached to a terminal and could not prompt for a
missing password.
4 Some sort of fatal protocol error was detected.
5 There was a syntax error in the arguments to fetchmail,
or a pre- or post-connect command failed.
6 The run control file had bad permissions.
7 There was an error condition reported by the server.
Can also fire if fetchmail timed out while waiting for
the server.
8 Client-side exclusion error. This means fetchmail
either found another copy of itself already running, or
failed in such a way that it isn't sure whether another
copy is running.
9 The user authentication step failed because the server
responded "lock busy". Try again after a brief pause!
This error is not implemented for all protocols, nor
for all servers. If not implemented for your server,
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"3" will be returned instead, see above. May be
returned when talking to qpopper or other servers that
can respond with "lock busy" or some similar text con-
taining the word "lock".
10 The fetchmail run failed while trying to do an SMTP
port open or transaction.
11 Fatal DNS error. Fetchmail encountered an error while
performing a DNS lookup at startup and could not pro-
ceed.
12 BSMTP batch file could not be opened.
13 Poll terminated by a fetch limit (see the --fetchlimit
option).
14 Server busy indication.
23 Internal error. You should see a message on standard
error with details.
24 - 26, 28, 29
These are internal codes and should not appear exter-
nally.
When fetchmail queries more than one host, return status is
0 if any query successfully retrieved mail. Otherwise the
returned error status is that of the last host queried.
FILES
~/.fetchmailrc
default run control file
~/.fetchids
default location of file recording last message UIDs
seen per host.
~/.fetchmail.pid
lock file to help prevent concurrent runs (non-root
mode).
~/.netrc
your FTP run control file, which (if present) will be
searched for passwords as a last resort before prompt-
ing for one interactively.
/var/run/fetchmail.pid
lock file to help prevent concurrent runs (root mode,
Linux systems).
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/etc/fetchmail.pid
lock file to help prevent concurrent runs (root mode,
systems without /var/run).
ENVIRONMENT
FETCHMAILHOME
If this environment variable is set to a valid and
existing directory name, fetchmail will read $FETCH-
MAILHOME/fetchmailrc (the dot is missing in this case),
$FETCHMAILHOME/.fetchids and $FETCHMAILHOME/.fetch-
mail.pid rather than from the user's home directory.
The .netrc file is always looked for in the the invok-
ing user's home directory regardless of FETCHMAILHOME's
setting.
FETCHMAILUSER
If this environment variable is set, it is used as the
name of the calling user (default local name) for pur-
poses such as mailing error notifications. Otherwise,
if either the LOGNAME or USER variable is correctly set
(e.g. the corresponding UID matches the session user
ID) then that name is used as the default local name.
Otherwise getpwuid(3) must be able to retrieve a pass-
word entry for the session ID (this elaborate logic is
designed to handle the case of multiple names per
userid gracefully).
FETCHMAIL_DISABLE_CBC_IV_COUNTERMEASURE
(since v6.3.22): If this environment variable is set
and not empty, fetchmail will disable a countermeasure
against an SSL CBC IV attack (by setting
SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS). This is a secu-
rity risk, but may be necessary for connecting to cer-
tain non-standards-conforming servers. See fetchmail's
NEWS file and fetchmail-SA-2012-01.txt for details.
Earlier fetchmail versions (v6.3.21 and older) used to
disable this countermeasure, but v6.3.22 no longer does
that as a safety precaution.
FETCHMAIL_INCLUDE_DEFAULT_X509_CA_CERTS
(since v6.3.17): If this environment variable is set
and not empty, fetchmail will always load the default
X.509 trusted certificate locations for SSL/TLS CA cer-
tificates, even if --sslcertfile and --sslcertpath are
given. The latter locations take precedence over the
system default locations. This is useful in case there
are broken certificates in the system directories and
the user has no administrator privileges to remedy the
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fetchmail reference manual fetchmail(1)
problem.
HOME_ETC
If the HOME_ETC variable is set, fetchmail will read
$HOME_ETC/.fetchmailrc instead of ~/.fetchmailrc.
If HOME_ETC and FETCHMAILHOME are both set, HOME_ETC
will be ignored.
SOCKS_CONF
(only if SOCKS support is compiled in) this variable is
used by the socks library to find out which configura-
tion file it should read. Set this to /dev/null to
bypass the SOCKS proxy.
SIGNALS
If a fetchmail daemon is running as root, SIGUSR1 wakes it
up from its sleep phase and forces a poll of all non-skipped
servers. For compatibility reasons, SIGHUP can also be used
in 6.3.X but may not be available in future fetchmail ver-
sions.
If fetchmail is running in daemon mode as non-root, use
SIGUSR1 to wake it (this is so SIGHUP due to logout can
retain the default action of killing it).
Running fetchmail in foreground while a background fetchmail
is running will do whichever of these is appropriate to wake
it up.
BUGS, LIMITATIONS, AND KNOWN PROBLEMS
Please check the NEWS file that shipped with fetchmail for
more known bugs than those listed here.
Fetchmail cannot handle user names that contain blanks after
a "@" character, for instance "demonstr@ti on". These are
rather uncommon and only hurt when using UID-based --keep
setups, so the 6.3.X versions of fetchmail won't be fixed.
Fetchmail cannot handle configurations where you have multi-
ple accounts that use the same server name and the same
login. Any user@server combination must be unique.
The assumptions that the DNS and in particular the check-
alias options make are not often sustainable. For instance,
it has become uncommon for an MX server to be a POP3 or IMAP
server at the same time. Therefore the MX lookups may go
away in a future release.
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fetchmail reference manual fetchmail(1)
The mda and plugin options interact badly. In order to col-
lect error status from the MDA, fetchmail has to change its
normal signal handling so that dead plugin processes don't
get reaped until the end of the poll cycle. This can cause
resource starvation if too many zombies accumulate. So
either don't deliver to a MDA using plugins or risk being
overrun by an army of undead.
The --interface option does not support IPv6 and it is
doubtful if it ever will, since there is no portable way to
query interface IPv6 addresses.
The RFC822 address parser used in multidrop mode chokes on
some @-addresses that are technically legal but bizarre.
Strange uses of quoting and embedded comments are likely to
confuse it.
In a message with multiple envelope headers, only the last
one processed will be visible to fetchmail.
Use of some of these protocols requires that the program
send unencrypted passwords over the TCP/IP connection to the
mailserver. This creates a risk that name/password pairs
might be snaffled with a packet sniffer or more sophisti-
cated monitoring software. Under Linux and FreeBSD, the
--interface option can be used to restrict polling to avail-
ability of a specific interface device with a specific local
or remote IP address, but snooping is still possible if (a)
either host has a network device that can be opened in
promiscuous mode, or (b) the intervening network link can be
tapped. We recommend the use of ssh(1) tunnelling to not
only shroud your passwords but encrypt the entire conversa-
tion.
Use of the %F or %T escapes in an mda option could open a
security hole, because they pass text manipulable by an
attacker to a shell command. Potential shell characters are
replaced by '_' before execution. The hole is further
reduced by the fact that fetchmail temporarily discards any
suid privileges it may have while running the MDA. For max-
imum safety, however, don't use an mda command containing %F
or %T when fetchmail is run from the root account itself.
Fetchmail's method of sending bounces due to errors or spam-
blocking and spam bounces requires that port 25 of localhost
be available for sending mail via SMTP.
If you modify ~/.fetchmailrc while a background instance is
running and break the syntax, the background instance will
die silently. Unfortunately, it can't die noisily because
we don't yet know whether syslog should be enabled. On some
systems, fetchmail dies quietly even if there is no syntax
fetchmail Last change: fetchmail 6.3.22 57
fetchmail reference manual fetchmail(1)
error; this seems to have something to do with buggy termi-
nal ioctl code in the kernel.
The -f - option (reading a configuration from stdin) is
incompatible with the plugin option.
The 'principal' option only handles Kerberos IV, not V.
Interactively entered passwords are truncated after 63 char-
acters. If you really need to use a longer password, you
will have to use a configuration file.
A backslash as the last character of a configuration file
will be flagged as a syntax error rather than ignored.
The BSMTP error handling is virtually nonexistent and may
leave broken messages behind.
Send comments, bug reports, gripes, and the like to the
An is available at the fetchmail home page, it should also
accompany your installation.
AUTHOR
Fetchmail is currently maintained by Matthias Andree and Rob
Funk with major assistance from Sunil Shetye (for code) and
Rob MacGregor (for the mailing lists).
Most of the code is from . Too many other people to name
here have contributed code and patches.
This program is descended from and replaces popclient, by ;
the internals have become quite different, but some of its
interface design is directly traceable to that ancestral
program.
This manual page has been improved by Matthias Andree,
R. Hannes Beinert, and H['e]ctor Garc['i]a.
ATTRIBUTES
See attributes(5) for descriptions of the following
attributes:
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fetchmail reference manual fetchmail(1)
+---------------+------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+------------------+
|Availability | mail/fetchmail |
+---------------+------------------+
|Stability | Committed |
+---------------+------------------+
SEE ALSO
README, README.SSL, README.SSL-SERVER, mutt(1), elm(1),
mail(1), sendmail(8), popd(8), imapd(8), netrc(5).
APPLICABLE STANDARDS
Note that this list is just a collection of references and
not a statement as to the actual protocol conformance or
requirements in fetchmail.
SMTP/ESMTP:
RFC 821, RFC 2821, RFC 1869, RFC 1652, RFC 1870, RFC
1983, RFC 1985, RFC 2554.
mail:
RFC 822, RFC 2822, RFC 1123, RFC 1892, RFC 1894.
POP2:
RFC 937
POP3:
RFC 1081, RFC 1225, RFC 1460, RFC 1725, RFC 1734, RFC
1939, RFC 1957, RFC 2195, RFC 2449.
APOP:
RFC 1939.
RPOP:
RFC 1081, RFC 1225.
IMAP2/IMAP2BIS:
RFC 1176, RFC 1732.
IMAP4/IMAP4rev1:
RFC 1730, RFC 1731, RFC 1732, RFC 2060, RFC 2061, RFC
2195, RFC 2177, RFC 2683.
ETRN:
RFC 1985.
ODMR/ATRN:
RFC 2645.
OTP: RFC 1938.
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fetchmail reference manual fetchmail(1)
LMTP:
RFC 2033.
GSSAPI:
RFC 1508, RFC 1734,
TLS: RFC 2595.
NOTES
This software was built from source available at
https://java.net/projects/solaris-userland. The original
community source was downloaded from http://down-
load.berlios.de/fetchmail/fetchmail-6.3.22.tar.bz2
Further information about this software can be found on the
open source community website at http://fetch-
mail.berlios.de/.
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