System Administration Guide: Resource Management and Network Services

Chapter 27 What's New With Mail Services (Reference)

Chapter 24, Mail Services (Overview) provides an introduction to the components of mail services and a description of a typical mail configuration. Chapter 25, Mail Services (Tasks) explains how to set up and administer an electronic mail system with standard configuration files. Chapter 26, Mail Services (Reference) describes in greater detail the components of mail services. Chapter 26, Mail Services (Reference) also describes the mail service programs and files, the mail routing process, and the interactions of sendmail with name services. This chapter describes the new features that are included in version 8.12 of sendmail, the version that is in this Solaris 9 release. You can also read about changes to mail.local, mailstats, and makemap. This chapter also describes a new maintenance utility, editmap. The following list can help you in your search on a specific topic.

For details that are not covered in this chapter, see the man pages for sendmail(1M), mail.local(1M), mailstats(1), makemap(1M), and editmap(1M).

Changes to sendmail

This section contains information on the following topics.

New Configuration File, submit.cf

Version 8.12 of sendmail includes an additional configuration file, /etc/mail/submit.cf. This new file, submit.cf, is used to run sendmail in mail-submission program mode instead of daemon mode. Mail-submission program mode, unlike daemon mode, does not require root privilege, so this new paradigm provides better security.

See the following list of functions for submit.cf:

Note the following:

Functions That Distinguish sendmail.cf From submit.cf

The sendmail.cf configuration file is for the daemon mode. When using this file, sendmail is acting as a mail transfer agent (MTA), which is started by root.


/usr/lib/sendmail -L sm-mta -bd -q1h

See the following list of other distinguishing functions for sendmail.cf:

Functional Changes in sendmail

With the addition of submit.cf, the following functional changes have occurred:

New or Deprecated Command-Line Options

The following table describes new command-line options for sendmail. Other command-line options are described in the sendmail(1M) man page.

Table 27–1 New Command-Line Options for sendmail

Option 

Description 

-Ac

Indicates that you want to use the configuration file, submit.cf, even if the operation mode does not indicate an initial mail submission. For more information about submit.cf, refer to New Configuration File, submit.cf.

-Am

Indicates that you want to use the configuration file, sendmail.cf, even if the operation mode indicates an initial mail submission. For more information, refer to New Configuration File, submit.cf.

-bP

Indicates that you are printing the number of entries in each queue. 

-G

Indicates that the message that is being submitted from the command line is for relaying, not for initial submission. The message is rejected if the addresses are not fully qualified. No canonicalization is done. As is noted in the Release Notes that are part of the sendmail distribution on ftp://ftp.sendmail.org, improperly formed messages might be rejected in future releases.

-L tag

Sets the identifier that is used for syslog messages to the supplied tag.

-q[!]I substring

Processes only jobs that contain this substring of one of the recipients. When ! is added, the option processes only jobs that do not have this substring of one of the recipients.

-q[!]R substring

Processes only jobs that contain this substring of the queue ID. When ! is added, the option processes only jobs that do not have this substring of the queue ID.

-q[!]S substring

Processes only jobs that contain this substring of the sender. When ! is added, the option processes only jobs that do not have this substring of the sender.

-qf

Processes saved messages in the queue once, without using the fork system call, and runs the process in the foreground. Refer to the fork(2) man page.

-qGname

Processes only the messages in the name queue group.

-qptime

Processes saved messages in the queue at a specific interval of time with a single child that is forked for each queue. The child sleeps between queue runs. This new option is similar to the -qtime, which periodically forks a child to process the queue.

-U

As is noted in the Release Notes that are part of the sendmail distribution on ftp://ftp.sendmail.org, this option is not available in version 8.12. Mail user agents should use the -G argument.

New and Revised Configuration File Options and Related Topics

This section contains a table of new and revised configuration file options and information on the following related topics.

When you declare these options, use one of the following syntaxes.


O OptionName=argument          # for the configuration file
-OOptionName=argument          # for the command line
define(`m4Name',argument)     # for m4 configuration

If you need to build a new sendmail.cf file, refer to Building the sendmail.cf Configuration File (Task) in Chapter 25, Mail Services (Tasks).

The following table describes new and revised options for sendmail.

Table 27–2 New and Revised Options for sendmail

Option 

Description 

BadRcptThrottle

m4 name: confBAD_RCPT_THROTTLE

Argument: number

The new option limits the rate at which recipients in the SMTP envelope are accepted after a threshold number of recipients has been rejected. 

ClientPortOptions

For details, see New ClientPortOptions Option.

ConnectionRateThrottle

m4 name: confCONNECTION_RATE_THROTTLE

Argument: number

The option ConnectionRateThrottle now limits the number of connections per second to each daemon, not the total number of connections.

ControlSocketName

m4 name: confCONTROL_SOCKET_NAME

Argument: filename. The recommended socket name is /var/spool/mqueue/.smcontrol. For security, this UNIX domain socket must be in a directory that is accessible only by root.

When this new option is set, the option creates a control socket for daemon management. This option enables an external program to control and query the status of the running sendmail daemon by way of a named socket. The socket is similar to the ctlinnd interface to the INN news server. If this option is not set, no control socket is available.

DaemonPortOptions

For details, see Changes to DaemonPortOptions Option.

DataFileBufferSize

m4 name: confDF_BUFFER_SIZE

Argument: number

The new option controls the maximum size (in bytes) of a memory-buffered data (df) file before a disk-based file is used. The default is 4096 bytes. You should not have to change the default for the Solaris operating environment.

DeadLetterDrop

m4 name: confDEAD_LETTER_DROP

Argument: filename

The new option, which you should not need to set, defines the location of the system-wide dead.letter file, which was formerly hard-coded to /usr/tmp/dead.letter.

DelayLA

m4 name: confDELAY_LA

Argument: number

If this new option is set to a value that is greater than zero, the option does the following:  

Delays connections by one second when the load averages exceed a specified value 

Delays the execution of most SMTP commands by one second 

Otherwise, if the option is not set, the default value, which is zero, does not change the behavior of sendmail.

DeliverByMin

m4 name: confDELIVER_BY_MIN

Argument: time

The new option enables a client to specify a minimum amount of time for an email message to be delivered, as specified in RFC 2852, Deliver By SMTP Service Extension. 

If the time is set to zero, no time is listed. 

If the time is set to less than zero, the extension is not offered. 

If the time is set to greater than zero, the extension is listed as the minimum time for the EHLO keyword, DELIVERBY.

DirectSubmissionModifiers

m4 name: confDIRECT_SUBMISSION_MODIFIERS

Argument: modifiers

The new option defines ${daemon_flags} for direct (command-line) submissions. If this option is not set, the value of ${daemon_flags} is either CC f, if the option -G is used, or c u.

DontBlameSendmail

You can use the following new arguments. 

The argument, NonRootSafeAddr, has been added. When sendmail does not have enough privileges to run a .forward program or deliver to a file as the owner of that file, addresses are marked unsafe. Furthermore, if RunAsUser is set, users cannot use programs or deliver to files in their .forward programs. Use NonRootSafeAddr to resolve these problems.

DoubleBounceAddress

m4 name: confDOUBLE_BOUNCE_ADDRESS

Argument: address. The default is postmaster.

If an error occurs when sendmail is sending an error message, sendmail sends the "double-bounced" error message to the address that is specified by the argument to this option.

FallBackMXhost

m4 name: confFALLBACK_MX

Argument: fully qualified domain name. 

This option now includes MX record lookups. To use the old behavior of no MX record lookups, you must put the name in square brackets. 

FastSplit

m4 name: confFAST_SPLIT

Argument: number. The default value is one.

This new option does the following: 

If the option is set to a value greater than zero, the initial MX lookups on addresses are suppressed when they are sorted, which might result in faster envelope splitting. 

If the mail is submitted from the command line, the value can limit the number of processes that are used to deliver the envelopes. 

If more envelopes are created, the envelopes are put in the queue and must be resolved with a queue run. 

LDAPDefaultSpec

m4 name: confLDAP_DEFAULT_SPEC

Argument: Class switch with appropriate definition (for example, -hhost, -pport, -dbind DN).

The new option allows a default map specification for LDAP maps. The assigned default settings are used for all LDAP maps unless other individual map specifications are made with the K command. Set this option before defining any LDAP maps.

MailboxDatabase

m4 name: confMAILBOX_DATABASE

Argument: pw, which uses getpwnam(), is the default value. No other values are supported.

The new option specifies the type of mailbox database that is used to check for local recipients.  

MaxHeadersLength

m4 name: confMAX_HEADERS_LENGTH

Argument: number

This option specifies a maximum length for the sum of all headers and can be used to prevent a denial-of-service attack. The default is 32768. A warning is issued if a value less than 16384 is used. You should not have to change the default value for the Solaris operating environment.  

MaxMimeHeaderLength

m4 name: confMAX_MIME_HEADER_LENGTH

Argument: number

This option sets the maximum length of certain MIME header field values to x number of characters. Also, for parameters within headers, you can specify a maximum length of y. The combined values look like x/y. If y is not specified, half of x is used. If no values are set, the default is 0, which means no checks are made. This option is intended to protect mail user agents from buffer-overflow attacks. The suggested values are in the range of 256/128 to 1024/256. A warning is issued if values less than 128/40 are used.

MaxQueueChildren

m4 name: confMAX_QUEUE_CHILDREN

Argument: number

This new option limits the number of concurrently active queue-runner processes to the number that is specified in the argument. The option helps to limit the system resources that are used when the queue is processed. When the total number of queue runners for multiple queue groups exceeds the defined argument, the remaining queue groups are run later. 

MaxRecipientsPerMessage

m4 name: confMAX_RCPTS_PER_MESSAGE

Argument: number

If this option is set, the option allows no more than the specified number of recipients in an SMTP envelope. The minimum argument is 100. You can still declare this option from both the command line and the configuration file. However, normal users can now set the option from the command line to enable the override of messages that are submitted through sendmail -bs. In this instance, sendmail does not relinquish its root privileges.

MaxRunnersPerQueue

m4 name: confMAX_RUNNERS_PER_QUEUE

Argument: number. The default is one. Consider your resources carefully and do not set this value too high.

This new option specifies the maximum number of queue runners per queue group. The queue runners work in parallel on a queue group's messages. This behavior is useful when the processing of a message might delay the processing of subsequent messages. 

NiceQueueRun

m4 name: confNICE_QUEUE_RUN

Argument: number

This new option sets the priority of queue runners. Refer to the nice(1) man page.

PidFile

m4 name: confPID_file

Argument: See Additional Arguments for the PidFile and ProcessTitlePrefix Options.

This new option defines the location of the pid file. The file name is macro expanded before being opened. The default is /var/run/sendmail.pid.

PrivacyOptions

For details, see Changes to the PrivacyOptions Option.

ProcessTitlePrefix

m4 name: confPROCESS_TITLE_PREFIX

Argument: See Additional Arguments for the PidFile and ProcessTitlePrefix Options.

The new option specifies a prefix string for the process title that is shown in /usr/ucb/ps auxww listings. The string is macro processed. You should not have to make any changes for the Solaris operating environment.

QueueFileMode

m4 name: confQUEUE_FILE_MODE

Argument: number

This new option provides the default permissions in octal for queue files. If this option is not set, sendmail uses 0600. However, if the option's real and effective user ID is different, sendmail uses 0644.

QueueLA

m4 name: confQUEUE_LA

Argument: number

The default value has changed from eight to eight times the number of processors online when the system starts. For single-processor machines, this change has no effect. Changing this value overrides the default and prevents the number of processors from being considered. Therefore, the effect of any value changes should be well understood. 

QueueSortOrder

m4 name: confQUEUE_SORT_ORDER

This option sets the algorithm that is used for sorting the queue. The default value is priority, which sorts the queue by message priority. Note the following changes.

The host argument now reverses the host name before sorting, which means domains are grouped to run through the queue together. This improvement provides better opportunities for use of the connection cache, if available.

The new filename argument sorts the queue by file name. This behavior avoids the opening and reading of each queue file when preparing to run the queue.

The new modification argument sorts the queue by time of modification, starting with the oldest entries of the qf file.

The new random argument sorts the queue randomly, which avoids contention, if several queue runners have manually been started.

For more information, refer to QueueSortOrder in the sendmail(1M) man page.

RefuseLA

m4 name: confREFUSE_LA

Argument: number

The default value has changed from 12 to 12 times the number of processors online when the system starts. For single-processor machines, this change has no effect. A change of this value overrides the default and prevents the number of processors from being considered. Therefore, the effect of any value changes should be well understood. 

ResolverOptions

Two changes have been made. 

When attempting to canonify a host name, some name servers that are down return a temporary failure message, SERVFAIL, for IPv6 T_AAAA lookups. You can use this new argument, WorkAroundBrokenAAAA, to avoid this behavior.

Also, the RES_USE_INET6 argument is controlled by a new flag, use_inet6. For more information, refer to the resolver(3RESOLV) man page.

RrtImpliesDsn

m4 name: confRRT_IMPLIES_DSN

Argument: true or false

If the new option is set, a “Return-Receipt-To:” header causes the request of a delivery status notification (DSN), which is sent to the envelope sender. The DSN is not sent to the address that is specified in the header. 

SendMimeErrors

m4 name: confMIME_FORMAT_ERRORS

Argument: true or false.

The default is now true.

SharedMemoryKey

m4 name: confSHARED_MEMORY_KEY

Argument: number.

This new option permits you to use shared memory, if shared memory is available, to store free space for queue file systems. This option minimizes the number of system calls to check for available space. 

SuperSafe

m4 name: confSAFE_QUEUE

Argument: true, false, or interactive. The default and recommended value is true. Avoid using false.

If this option is set to true, the queue file is always instantiated, even if you are attempting immediate delivery. You can use the interactive value together with DeliveryMode=i to skip some synchronization calls that are doubled in the code execution path for this mode.

Timeout

For details, see Changes to the Timeout Option.

TrustedUser

m4 name: confTRUSTED_USER

Argument: user name or user numeric ID.

The new option enables you to specify a user name (instead of root) to own important files. If this option is set, generated alias databases and the control socket—if configured—are automatically owned by this user. This option requires HASFCHOWN. For information about HASFCHOWN, see Flags Used and Not Used to Compile sendmail.

Only TrustedUser, root, and class t ($=t) users can rebuild the alias map.

UseMSP

m4 name: confUSE_MSP

Argument: true or false. The default is false.

This new option permits group-writable queue files, if the group is the same as that of a set-group-id sendmail binary. In submit.cf, this option must be set to true.

XscriptFileBufferSize

m4 name: confXF_BUFFER_SIZE

Argument: number.

The new option controls the maximum size (in bytes) of a memory-buffered transcript (xf) file before a disk-based file is used. The default is 4096 bytes. You should not have to change this default for the Solaris operating environment.

Deprecated and Unsupported Configuration File Options for sendmail

Refer to the following table for a list of deprecated configuration file options. The table includes the AutoRebuildAliases option, which is not in version 8.12 of sendmail.

Table 27–3 Deprecated and Unsupported Configuration File Options for sendmail

Option 

Description 

AutoRebuildAliases

Because a denial-of-service attack could occur if this option is set, this option is not in version 8.12 of sendmail. Refer to the Release Notes that are part of the sendmail distribution at ftp://ftp.sendmail.org. A user could kill the sendmail process while the aliases file is being rebuilt and leave the file in an inconsistent state.

Furthermore, because AutoRebuildAliases is not available, newaliases must be run manually now in order for changes to /etc/mail/aliases to become effective. Also, you must remember that because sendmail is no longer setuid root, only root can run newaliases.

MeToo

This option, which now defaults to True, has been deprecated. Refer to the Release Notes that are part of the sendmail distribution at ftp://ftp.sendmail.org.

UnsafeGroupWrites

This option is deprecated. If required, you should now use the GroupWritableForwardFileSafe and GroupWritableIncludeFileSafe arguments for the DontBlameSendmail option.

UseErrorsTo

This option is deprecated. Furthermore, because this option violates RFC 1123, you should avoid using this option. 

New ClientPortOptions Option

The new ClientPortOptions option is for outgoing connections and is similar to the DaemonPortOptions option. This option sets the client SMTP options, which are a sequence of key=value pairs. To declare this option, use one of the following syntaxes. For formatting purposes, the example includes two pairs. However, you can apply one or more pairs.


O ClientPortOptions=pair,pair              # for the configuration file
-OClientPortOptions=pair,pair              # for the command line
define(`confCLIENT_OPTIONS',`pair,pair')   # for m4 configuration

If you need to build a new sendmail.cf file, refer to Building the sendmail.cf Configuration File (Task) in Chapter 25, Mail Services (Tasks).

The following table describes the new keys for this option.

Table 27–4 New Keys for ClientPortOptions

Key 

Description 

Addr

Specifies the address mask. The value can be a numeric address in dot notation or a network name. If the pair is omitted, the default is INADDR_ANY, which accepts connections from any network.

Family

Specifies the address family. The key's default is inet for AF_INET. Other values are inet6 for AF_INET6, iso for AF_ISO, ns for AF_NS, and x.25 for AF_CCITT.

Listen

Specifies the size of the listen queue. The key defaults to 10. You should not have to change this default for the Solaris operating environment.

Port

Specifies the name and number of the listening port. The key defaults to smtp.

RcvBufSize

Specifies the size of the TCP/IP send buffer. The key has no default value, which means that no size specifications are automatically made. If the option is set to a value that is greater than zero, that value is used. You should not have to limit the size of this buffer for the Solaris operating environment. 

Modifier

Specifies flags for sendmail:

The h flag uses the name that corresponds to the outgoing interface address for the HELO or EHLO commands, whether it was chosen by the connection parameter or by the default.

The A flag disables AUTH. This flag can also be used with the Modifier key for DaemonPortOptions. Refer to Changes to DaemonPortOptions Option.

The S flag turns off the use of or the offer to use STARTTLS when email is being delivered or is being received.

Changes to DaemonPortOptions Option

The following tables describe the new features.

To declare this option, use one of the following syntaxes. In the example, pair refers to key=value. For formatting purposes, the example includes two pairs. However, you can apply one or more pairs.


O DaemonPortOptions=pair,pair              # for the configuration file
-ODaemonPortOptions=pair,pair              # for the command line
define(`confDAEMON_OPTIONS',`pair,pair')   # for m4 configuration 

Note –

To avoid security risks, sendmail relinquishes its root permissions when you set this option from the command line.


If you need to build a new sendmail.cf file, refer to Building the sendmail.cf Configuration File (Task) in Chapter 25, Mail Services (Tasks).

The following table describes new and revised keys for the DaemonPortOptions option.

Table 27–5 New and Revised Keys for DaemonPortOptions

Key 

Description 

Name

A new key that specifies a user-definable name for sendmail. This key is used for error messages and for logging. The default is MTA.

Modifier

A new key that specifies values for sendmail that can be listed in a sequence without delimiters. For a list of values, see Table 27–6.

Family

Unless a Family is specified in a DaemonPortOptions option, inet is now the only default. If IPv6 users also want to listen on IPv6 interfaces, they can configure additional sockets into sendmail.cf by adding a Family=inet6 setting to a DaemonPortOptions option.

The following table describes the values for the new Modifier key.

Table 27–6 Values for the New Modifier Key

Value 

Description 

A

Disables AUTH by overriding the Modifier value of a.

Can be used with the Modifier key for ClientPortOptions. Refer to New ClientPortOptions Option.

C

Does not perform host-name canonification. 

E

Disallows the ETRN command.

O

Ignores the socket if a failure should occur. 

S

Turns off the use or the offer to use STARTTLS when email is being delivered or is being received.

Can be used with the Modifier key for ClientPortOptions.

a

Requires authentication. 

b

Binds to the interface that receives the mail. 

c

Performs host-name canonification. Use this value only in configuration file declarations. 

f

Requires fully qualified host names. Use this value only in configuration file declarations. 

h

Uses the interface's name for the outgoing HELO command.

u

Allows unqualified addresses. Use this value only in configuration file declarations. 

Additional Arguments for the PidFile and ProcessTitlePrefix Options

The following table describes additional macro-processed arguments for the PidFile and ProcessTitlePrefix options. For more information about these options, see Table 27–2.

Table 27–7 Arguments for the PidFile and ProcessTitlePrefix Options

Macro 

Description 

${daemon_addr}

Provides daemon address (for example, 0.0.0.0) 

${daemon_family}

Provides daemon family (for example, inet, and inet6)

${daemon_info}

Provides daemon information (for example, SMTP+queueing@00:30:00) 

${daemon_name}

Provides daemon name (for example, MSA) 

${daemon_port}

Provides daemon port (for example, 25) 

${queue_interval}

Provides queue run interval (for example, 00:30:00) 

Changes to the PrivacyOptions Option

New and revised arguments for PrivacyOptions (popt) are described in the following table. You can declare this option from the command line without sendmail relinquishing its root privilege. To declare this sendmail option, use one of the following syntaxes.


O PrivacyOptions=argument                # for the configuration file
-OPrivacyOptions=argument                # for the command line
define(`confPRIVACY_FLAGS',`argument')   # for m4 configuration

If you need to build a new sendmail.cf file, refer to Building the sendmail.cf Configuration File (Task) in Chapter 25, Mail Services (Tasks).

The following table provides descriptions of new and revised arguments for the PrivacyOptions option.

Table 27–8 New and Revised Arguments for PrivacyOptions

Argument 

Description 

goaway

This argument no longer accepts the following flags: noetrn, restrictmailq, restrictqrun, restrictexpand, nobodyreturn, and noreceipts.

nobodyreturn

This argument instructs sendmail not to include the body of the original message in delivery status notifications.

noreceipts

When this argument is set, delivery status notification (DSN) is not announced. 

restrictexpand

This argument instructs sendmail to drop privileges when the -bv option is given by users who are neither root nor TrustedUser. The users cannot read private aliases, .forward files, or :include: files. This argument also overrides the -v command-line option.

Changes to the Timeout Option

The following table provides information about the changes to the Timeout option. Specifically, this sendmail option has some new keywords and a new value for ident. In the Solaris operating environment, you should not need to change the default values for the keywords that are listed in the table. However, if you choose to make a change, use the keyword=value syntax. The value is a time interval. Refer to the following examples.


O Timeout.keyword=value   # for the configuration file
-OTimeout.keyword=value   # for the command line
define(`m4_name', value) # for m4 configuration

If you need to build a new sendmail.cf file, refer to Building the sendmail.cf Configuration File (Task) in Chapter 25, Mail Services (Tasks).


Note –

To avoid security risks, sendmail relinquishes its root permissions when you set this option from the command line.


Table 27–9 New and Revised Settings for Timeout

Keyword 

Default Value 

Description 

aconnect

0

m4 name: confTO_ACONNECT

Limits the total time to wait for all connections to succeed for a single delivery attempt. The maximum value is unspecified. 

control

2m

m4 name: confTO_CONTROL

Limits the total time that is dedicated to completing a control socket request. 

ident

5s

m4 name: confTO_IDENT

Defaults to 5 seconds—instead of 30 seconds—to prevent the common delays that are associated with mailing to a site that drops IDENT packets. No maximum value is specified.

lhlo

2m

m4 name: confTO_LHLO

Limits the time to wait for a reply from an LMTP LHLO command. No maximum value is specified.

queuereturn

5d

m4 name: confTO_QUEUERETURN

Includes the value now, which immediately bounces entries from the queue without a delivery attempt.

resolver.retrans

varies

m4 name: confTO_RESOLVER_RETRANS

Sets the resolver's retransmission time interval in seconds, which applies to resolver.retrans.first and resolver.retrans.normal.

resolver.retrans.first

varies

m4 name: confTO_RESOLVER_RETRANS_FIRST

Sets the resolver's retransmission time interval in seconds for the first attempt to deliver a message. 

resolver.retrans.normal

varies

m4 name: confTO_RESOLVER_RETRANS_NORMAL

Sets the resolver's retransmission time interval in seconds for all resolver lookups, except the first delivery attempt. 

resolver.retry

varies

m4 name: confTO_RESOLVER_RETRY

Sets the number of times to retransmit a resolver query, which applies to Timeout.resolver.retry.first and Timeout.resolver.retry.normal.

resolver.retry.first

varies

m4 name: confTO_RESOLVER_RETRY_FIRST

Sets the number of times to retransmit a resolver query for the first attempt to deliver a message. 

resolver.retry.normal

varies

m4 name: confTO_RESOLVER_RETRY_NORMAL

Sets the number of times to retransmit a resolver query for all resolver lookups, except the first delivery attempt. 

New Defined Macros for sendmail

The following table describes new macros that are reserved for use by the sendmail program. The macros' values are assigned internally. For more information, refer to the sendmail(1M) man page.

Table 27–10 Defined Macros for sendmail

Macro 

Description 

${addr_type}

Identifies the current address as an envelope sender or a recipient address. 

${client_resolve}

Holds the result of the resolve call for ${client_name}: OK, FAIL, FORGED, or TEMP.

${deliveryMode}

Specifies the current delivery mode sendmail is using instead of the value of the DeliveryMode option.

${dsn_notify}, ${dsn_envid}, ${dsn_ret}

Holds the corresponding DSN parameter values. 

${if_addr}

Provides the interface's address for the incoming connection if the interface does not belong to the loopback net. This macro is especially useful for virtual hosting. 

${if_addr_out}, ${if_name_out}, ${if_family_out}

Avoids the reuse of ${if_addr}. Holds the following values respectively.

The address of the interface for the outgoing connection 

The host name of the interface for the outgoing connection 

The family of the interface for the outgoing connection 

${if_name}

Provides the interface's host name for the incoming connection and is especially useful for virtual hosting.  

${load_avg}

Checks and reports the current average number of jobs in the run queue. 

${msg_size}

Holds the value of the message size (SIZE=parameter) in an ESMTP dialogue before the message has been collected. Thereafter, the macro holds the message size as computed by sendmail and is used in check_compat. For information about check_compat, refer to Table 27–14.

${nrcpts}

Holds the number of validated recipients. 

${ntries}

Holds the number of delivery attempts. 

${rcpt_mailer}, ${rcpt_host}, ${rcpt_addr}, ${mail_mailer}, ${mail_host}, ${mail_addr}

Holds the results of parsing the RCPT and MAIL arguments, which is the resolved right-hand side (RHS) triplet from the mail delivery agent ($#mailer), the host ($@host), and the user ($:addr).

New Macros Used to Build the sendmail Configuration File

In this section, you can find the following.

Table 27–11 New Macros Used to Build the sendmail Configuration File

Macro 

Description 

LOCAL_MAILER_EOL

Overrides the default end-of-line string for the local mailer. 

LOCAL_MAILER_FLAGS

Adds Return-Path: header by default.

MAIL_SETTINGS_DIR

Contains the path (including the trailing slash) for the mail settings directory. 

MODIFY_MAILER_FLAGS

Improves the *_MAILER_FLAGS. This macro sets, adds, or deletes flags.

RELAY_MAILER_FLAGS

Defines additional flags for the relay mailer. 

New MAX Macros

Use the following new macros to configure the maximum number of commands that can be received before sendmail slows its delivery. You can set these MAX macros at compile time. The maximum values in the following table also represent the current default values.

Table 27–12 New MAX Macros

Macro 

Maximum Value 

Commands Checked by Each Macro 

MAXBADCOMMANDS

25 

Unknown commands 

MAXNOOPCOMMANDS

20 

NOOP, VERB, ONEX, XUSR

MAXHELOCOMMANDS

HELO, EHLO

MAXVRFYCOMMANDS

VRFY, EXPN

MAXETRNCOMMANDS

ETRN


Note –

You can disable a macro's check by setting the macro's value to zero.


New and Revised m4 Configuration Macros for sendmail

This section contains a table of new and revised m4 configuration macros for sendmail. Use the following syntax to declare these macros.


symbolic_name(`value')

If you need to build a new sendmail.cf file, refer to Building the sendmail.cf Configuration File (Task) in Chapter 25, Mail Services (Tasks).

Table 27–13 New and Revised m4 Configuration Macros for sendmail

m4 Macro

Description 

FEATURE()

For details, refer to Changes to the FEATURE() Declaration.

LOCAL_DOMAIN()

This macro adds entries to class w ($=w).

MASQUERADE_EXCEPTION()

A new macro that defines hosts or subdomains that cannot be masqueraded. 

SMART_HOST()

This macro can now be used for bracketed addresses, such as user@[host].

VIRTUSER_DOMAIN() or VIRTUSER_DOMAIN_FILE()

When these macros are used, include $={VirtHost} in $=R. As a reminder, $=R is the set of host names that are allowed to relay.

Changes to the FEATURE() Declaration

Refer to the following tables for information about the specific changes to the FEATURE() declarations.

To use the new and revised FEATURE names, use the following syntax.


FEATURE(`name', `argument')

If you need to build a new sendmail.cf file, refer to Building the sendmail.cf Configuration File (Task) in Chapter 25, Mail Services (Tasks).

Table 27–14 New and Revised FEATURE() Declarations

Name of FEATURE()

Description 

compat_check

Argument: Refer to the example in the following paragraph. 

This new FEATURE() enables you to look for a key in the access map that consists of the sender address and the recipient address. This FEATURE() is delimited by the following string, <@>. sender@sdomain<@>recipient@rdomain is an example.

delay_checks

Argument: friend, which enables a spam-friend test, or hater, which enables a spam-hater test.

A new FEATURE() that delays all checks. By using FEATURE(`delay_checks'), the rule sets check_mail and check_relay are not called when a client connects or issues a MAIL command, respectively. Instead, these rule sets are called by the check_rcpt rule set. For details, refer to the /usr/lib/mail/README file.

dnsbl

Argument: This FEATURE()accepts a maximum of two arguments:

  • DNS server name

  • Rejection message

A new FEATURE() that you can include multiple times to check the return values for DNS lookups. Note that this FEATURE() enables you to specify the behavior of temporary lookup failures.

enhdnsbl

Argument: domain name. 

A new FEATURE() that is an enhanced version of dnsbl, which enables you to check the return values for DNS lookups. For more information, refer to /usr/lib/mail/README.

generics_entire_domain

Argument: None. 

A new FEATURE() that you can also use to apply genericstable to subdomains of $=G.

ldap_routing

Argument: For details, refer to the “Release Notes” in http://www.sendmail.org.

A new FEATURE() that implements LDAP address routing.

local_lmtp

Argument: Path name of an LMTP-capable mailer. The default is mail.local, which is LMTP capable in this Solaris release.

A FEATURE() that now sets the delivery status notification (DSN) diagnostic-code type for the local mailer to the proper value of SMTP.

local_no_masquerade

Argument: None. 

A new FEATURE() that you can use to avoid masquerading for the local mailer.

lookupdotdomain

Argument: None. 

A new FEATURE() that you can also use to look up the .domain in the access map.

nocanonify

Argument: canonify_hosts or nothing.

A FEATURE() that now includes the following features.

Enables a list of domains, as specified by CANONIFY_DOMAIN or CANONIFY_DOMAIN_FILE, to be passed to the $[ and $] operators for canonification.

Enables addresses that have only a host name, such as <user@host>, to be canonified, if canonify_hosts is specified as its parameter.

Adds a trailing dot to addresses with more than one component. 

no_default_msa

Argument: None. 

A new FEATURE() that turns off sendmail's default setting from m4–generated configuration files to “listen” on several different ports, an implementation of RFC 2476.

nouucp

Argument: reject, which does not allow the ! token, or nospecial, which does allow the ! token.

A FEATURE() that determines whether to allow the ! token in the local part of an address.

nullclient

Argument: None. 

A FEATURE() that now provides the full rule sets of a normal configuration, allowing anti-spam checks to be performed.

preserve_local_plus_detail

Argument: None. 

A new FEATURE() that enables you to preserve the +detail portion of the address when sendmail passes the address to the local delivery agent.

preserve_luser_host

Argument: None. 

A new FEATURE() that enables you to preserve the name of the recipient host, if LUSER_RELAY is used.

queuegroup

Argument: None. 

A new FEATURE() that enables you to select a queue group that is based on the full email address or on the domain of the recipient.

relay_mail_from

Argument: The domain is an optional argument.

A new FEATURE() that allows relaying if the mail sender is listed as a RELAY in the access map and is tagged with the From: header line. If the optional domain argument is given, the domain portion of the mail sender is also checked.

virtuser_entire_domain

Argument: None. 

A FEATURE() that you can now use to apply $={VirtHost}, a new class for matching virtusertable entries that can be populated by VIRTUSER_DOMAIN or VIRTUSER_DOMAIN_FILE.

FEATURE(`virtuser_entire_domain') can also apply the class $={VirtHost} to entire subdomains.

The following FEATURE() declarations are no longer supported.

Table 27–15 Unsupported FEATURE() Declarations

Name of FEATURE()

Replacement 

rbl

FEATURE(`dnsbl') and FEATURE(`enhdnsbl') replace this FEATURE(), which has been removed.

remote_mode

MASQUERADE_AS(`$S') replaces FEATURE(`remote_mode') in /usr/lib/mail/cf/subsidiary.mc. $S is the SMART_HOST value in sendmail.cf.

sun_reverse_alias_files

FEATURE(`genericstable').

sun_reverse_alias_nis

FEATURE(`genericstable').

sun_reverse_alias_nisplus

FEATURE(`genericstable').

Changes to the MAILER() Declaration

The MAILER() declaration specifies support for delivery agents. To declare a delivery agent, use the following syntax.


MAILER(`symbolic_name')

Note the following changes.

For more information about mailers, refer to Mailers. If you need to build a new sendmail.cf file, refer to Building the sendmail.cf Configuration File (Task) in Chapter 25, Mail Services (Tasks).

New Delivery Agent Flags

The following table describes new delivery agent flags, which by default are not set. These single-character flags are Boolean. You can set or unset a flag by including or excluding it in the F= statement of your configuration file, as shown in the following example.


Mlocal,    P=/usr/lib/mail.local, F=lsDFMAw5:/|@qSXfmnz9, S=10/30, R=20/40,
Mprog,     P=/bin/sh, F=lsDFMoqeu9, S=10/30, R=20/40, D=$z:/,
Msmtp,     P=[IPC], F=mDFMuX, S=11/31, R=21, E=\r\n, L=990,
Mesmtp,    P=[IPC], F=mDFMuXa, S=11/31, R=21, E=\r\n, L=990,
Msmtp8,    P=[IPC], F=mDFMuX8, S=11/31, R=21, E=\r\n, L=990,
Mrelay,    P=[IPC], F=mDFMuXa8, S=11/31, R=61, E=\r\n, L=2040,
Table 27–16 New Mailer Flags

Flag 

Description 

%

Mailers that use this flag do not attempt delivery to the initial recipient of a message or to queue runs unless the queued message is selected by using an ETRN request or one of the following queue options: -qI, -qR, or -qS.

1

This flag disables the ability of the mailer to send null characters (for example, \0).

2

This flag disables the use of ESMTP and requires that SMTP be used instead. 

6

This flag enables mailers to strip headers to 7 bit. 

New Equates for Delivery Agents

The following table describes new equates that you can use with the M delivery agent definition command. The following syntax shows you how to append new equates or new arguments to the equates that already exist in the configuration file.


Magent_name, equate, equate, ...

The following example includes the new W= equate. This equate specifies the maximum time to wait for the mailer to return after all data has been sent.


Msmtp, P=[IPC], F=mDFMuX, S=11/31, R=21, E=\r\n, L=990, W=2m

When you modify the definition of a value for m4 configuration, use the syntax that is provided in the following example.


define(`SMTP_MAILER_MAXMSGS', `1000')

The preceding example places a limit of 1000 on the number of messages that are delivered per connection on an smtp mailer.

If you need to build a new sendmail.cf file, refer to Building the sendmail.cf Configuration File (Task) in Chapter 25, Mail Services (Tasks).


Note –

Typically, you modify the equate definitions in the mailer directory only when you fine-tune.


Table 27–17 New Equates for Delivery Agents

Equate 

Description 

/=

Argument: Path to a directory 

Specifies a directory to apply chroot() to before the mailer program is executed

m=

Argument: Any of the following m4 values that have previously been defined with the define() routine

    SMTP_MAILER_MAXMSGS, for the smtp mailer


    LOCAL_MAILER_MAXMSGS, for the local mailer


    RELAY_MAILER_MAXMSGS, for the relay mailer


Limits the number of messages that are delivered per connection on an smtp, local, or relay mailer

W=

Argument: An increment of time 

Specifies the maximum time to wait for the return of the mailer after all data has been sent 

New Queue Features

The following list provides details about new queue features.

For task information, refer to Administering the Queue Directories (Task Map).

Changes for LDAP in sendmail

The following list describes changes in the use of the Lightweight Directory Access Protocol (LDAP) with sendmail.

The following table describes new LDAP map flags.

Table 27–19 New LDAP Map Flags

Flag 

Description 

-1

Requires a single match to be returned. If more than one match is returned, the results are the equivalent of no records being found. 

-r never|always|search|find

Sets the LDAP alias dereference option. 

-Z size

Limits the number of matches to return. 

New Built-in Mailer Feature

The old [TCP] built-in mailer is not available. Use the P=[IPC] built-in mailer instead. The interprocess communications ([IPC]) built-in mailer now enables delivery to a UNIX domain socket on systems that support it. You can use this mailer with LMTP delivery agents that listen on a named socket. An example mailer might resemble the following.


Mexecmail, P=[IPC], F=lsDFMmnqSXzA5@/:|, E=\r\n, 
S=10, R=20/40, T=DNS/RFC822/X-Unix, A=FILE /var/run/lmtpd

The first mailer argument in the [IPC] mailer is now checked for a legitimate value. The following table provides possible values for the first mailer argument.

Table 27–20 Possible Values for the First Mailer Argument

Value 

Description 

A=FILE

Use for UNIX domain socket delivery 

A=TCP

Use for TCP/IP connections 

A=IPC

Is no longer available as a first mailer argument 

New Rule Sets

The following table lists the new rule sets and describes what the rule sets do.

Table 27–21 New Rule Sets

Set 

Description 

check_eoh

Correlates information that is gathered between headers and checks for missing headers. This rule set is used with the macro storage map and is called after all of the headers have been collected.  

check_etrn

Uses the ETRN command (as check_rcpt uses RCPT).

check_expn

Uses the EXPN command (as check_rcpt uses RCPT).

check_vrfy

Uses the VRFY command (as check_rcpt uses RCPT).

The following list describes new rule set features.

Changes to Files

Note the following changes.

IPv6 Addresses in Configuration

In version 8.12 of sendmail, IPv6 addresses that are used in configuration should be prefixed with the IPv6: tag to identify the address properly. If you are not identifying an IPv6 address, a prefix tag is not used.

Changes to mail.local

The following table describes the new command-line options for the mail.local program, which is used by sendmail as a delivery agent for local mail.

Table 27–22 New Command-Line Options for mail.local

Option 

Description 

-7

Prevents the Local Mail Transfer Protocol (LMTP) mode from advertising 8BITMIME support in the LHLO response

-b

Causes a permanent error instead of a temporary error if a mailbox exceeds its quota 

mail.local is the default for LMTP mode. However, for this release, if you choose to use mail.local as the local delivery agent without being in LMTP mode, you need to do one of the following to set the S flag.

Use the following syntax for the configuration file.


MODIFY_MAILER_FLAGS(`LOCAL', `+S')      # for the configuration file

Alternately, perform the following two steps for m4 configuration.


define(`MODIFY_MAILER_FLAGS', `S')dnl   # first step
MAILER(local)dnl                        # second step

Note –

MODIFY_MAILER_FLAGS is a new macro that is used to build the configuration file. For details, refer to New Macros Used to Build the sendmail Configuration File.


For a complete review, refer to the mail.local(1M) man page.

Changes to mailstats

The mailstats program, which provides statistics on mailer usage, is packaged with the sendmail program. The following table describes new options in mailstats.

Table 27–23 New mailstats Options

Option 

Description 

-C filename

Specifies a sendmail configuration file

-p

Provides clear statistics in a program-readable mode 

-P

Also provides clear statistics in a program-readable mode, but this option does not truncate the statistics file 

For more information, refer to the mailstats(1) man page.

Changes to makemap

The makemap command creates keyed database files for sendmail. The following table describes new makemap options. When you declare options, use the following syntax.


makemap options class filename

When you use the preceding syntax, remember the following.

Table 27–24 New makemap Options

Option 

Description 

-C

Uses the specified sendmail configuration file for finding the TrustedUser option

-c

Uses the specified hash and btree cache size

-e

Allows an empty value from the right-hand side (RHS) 

-l

Lists map types that are supported 

-t

Specifies a different delimiter, instead of white space 

-u

Dumps (unmaps) the contents of the database to standard output 


Note –

If makemap is running as root, the ownership of the generated maps is automatically changed to the TrustedUser, as specified in the sendmail configuration file. For more information about the TrustedUser option, refer to Table 27–2.


For more information, refer to the makemap(1M) man page.

New Command, editmap

Use the new maintenance command, editmap, to query and edit single records in keyed database maps for sendmail. From the command line, use the following syntax.


editmap options maptype mapname key "value"

For a detailed description and a list of options, refer to the editmap(1M) man page.

Other Changes and Features of Interest

The following list describes other changes and features of interest.