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man pages section 5: File Formats

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Updated: Thursday, June 13, 2019
 
 

addresses (5)

Name

addresses - addresses and aliases for sendmail

Synopsis

/etc/mail/aliases


/etc/mail/aliases.db


/etc/mail/aliases.dir


/etc/mail/aliases.pag


~/.forward

Description

aliases(5)                       File Formats                       aliases(5)



NAME
       aliases, addresses, forward - addresses and aliases for sendmail

SYNOPSIS
       /etc/mail/aliases


       /etc/mail/aliases.db


       /etc/mail/aliases.dir


       /etc/mail/aliases.pag


       ~/.forward


DESCRIPTION
       These  files  contain  mail  addresses  or aliases, recognized by send-
       mail(8) for the local host:

       /etc/passwd

           Mail addresses (usernames) of local users.


       /etc/mail/aliases

           Aliases for the local host, in ASCII format.  Root  can  edit  this
           file to add, update, or delete local mail aliases.


       /etc/mail/aliases.{dir , pag}

           The aliasing information from /etc/mail/aliases, in binary ndbm(3C)
           format for use by sendmail(8). The program newaliases(8)  maintains
           these files.


       /etc/mail/aliases.db

           The  aliasing information from /etc/mail/aliases, in binary, Berke-
           ley DataBase format for use by sendmail(8). The  program  maintains
           these files.

           Depending   on   the  configuration  of  the  AliasFile  option  in
           /etc/mail/sendmail.cf, either the single  file  aliases.db  or  the
           pair  of files aliases.{dir, pag} is generated by newaliases(8). As
           shipped with Solaris, sendmail(8) supports both formats. If neither
           is specified, the Berkeley DataBase format which generates the sin-
           gle .db file is used.


       ~/.forward

           Addresses to which a user's mail is forwarded (see  Automatic  For-
           warding).



       In  addition,  the  NIS name services aliases map mail.aliases contains
       addresses and aliases available for use across the network.

   Addresses
       As distributed, sendmail(8) supports the following types of addresses:

   Local Usernames
         username



       Each local username is listed in the local host's /etc/passwd file.

   Local Filenames
         pathname



       Messages addressed to the absolute pathname of a file are  appended  to
       that file.

   Commands
         |command



       If  the  first  character  of  the address is a vertical bar (|), send-
       mail(8) pipes the message to the standard input of the command the  bar
       precedes.

   Internet-standard Addresses
         username@domain



       If  domain  does  not contain any `.' (dots), then it is interpreted as
       the name of a host in the current domain.  Otherwise,  the  message  is
       passed  to  a  mailhost  that  determines  how  to get to the specified
       domain. Domains are divided into subdomains separated by dots, with the
       top-level domain on the right.


       For example, the full address of John Smith could be:

         js@jsmachine.Podunk-U.EDU



       if he uses the machine named jsmachine at Podunk University.

   uucp Addresses
         ... [host!] host!username



       These  are  sometimes  mistakenly  referred to as ``Usenet'' addresses.
       uucp(1C) provides links to numerous sites throughout the world for  the
       remote copying of files.


       Other site-specific forms of addressing can be added by customizing the
       sendmail.cf configuration file. See sendmail(8) for  details.  Standard
       addresses are recommended.

   Aliases
   Local Aliases
       /etc/mail/aliases is formatted as a series of lines of the form

         aliasname:address[, address]



       aliasname  is  the name of the alias or alias group, and address is the
       address of a recipient in the group. Aliases can be nested. That is, an
       address  can  be  the  name  of another alias group. Because of the way
       sendmail(8) performs mapping from upper-case to lower-case, an  address
       that is the name of another alias group must not contain any upper-case
       letters.


       Lines beginning with white space are treated as continuation lines  for
       the preceding alias. Lines beginning with # are comments.

   Special Aliases
       An alias of the form:

         owner-aliasname : address



       sendmail  directs  error-messages  resulting  from mail to aliasname to
       address, instead of back to the person who sent the  message.  sendmail
       rewrites  the  SMTP  envelope  sender to match this, so owner-aliasname
       should always point to alias-request, and alias-request should point to
       the owner's actual address:

         owner-aliasname:      aliasname-request
         aliasname-request     address



       An alias of the form:

         aliasname: :include:pathname



       with  colons  as shown, adds the recipients listed in the file pathname
       to the aliasname alias. This allows a private  list  to  be  maintained
       separately from the aliases file.

   NIS Domain Aliases
       The  aliases file on the master NIS server is used for the mail.aliases
       NIS map, which can be made available to every  NIS  client.  Thus,  the
       /etc/mail/aliases* files on the various hosts in a network will one day
       be obsolete. Domain-wide aliases should  ultimately  be  resolved  into
       usernames  on specific hosts. For example, if the following were in the
       domain-wide alias file:

         jsmith:js@jsmachine



       then any NIS client could just mail to jsmith and not have to  remember
       the machine and username for John Smith.


       If  an  NIS  alias does not resolve to an address with a specific host,
       then the name of the NIS domain is used. There should be  an  alias  of
       the domain name for a host in this case.


       For example, the alias:

         jsmith:root



       sends  mail  on  an  NIS client to root@podunk-u if the name of the NIS
       domain is podunk-u.

   Automatic Forwarding
       When an alias (or address) is resolved to the name of  a  user  on  the
       local  host,  sendmail(8)  checks  for  a ~/.forward file, owned by the
       intended recipient, in that user's home directory, and  with  universal
       read  access. This file can contain one or more addresses or aliases as
       described above, each of which is sent a copy of the user's mail.


       Care must be taken to avoid creating addressing loops in the ~/.forward
       file.  When forwarding mail between machines, be sure that the destina-
       tion machine does not return the mail to the sender through the  opera-
       tion  of  any NIS aliases. Otherwise, copies of the message may bounce.
       Usually, the solution is to change the NIS alias to direct mail to  the
       proper destination.


       A  backslash before a username inhibits further aliasing. For instance,
       to invoke the vacation program, user js creates a ~/.forward file  that
       contains the line:

         \js, "|/usr/bin/vacation js"



       so  that  one  copy  of the message is sent to the user, and another is
       piped into the vacation program.


       The ~/.forward file can be used to specify special  "per  user"  exten-
       sions  by creating a .forward+extension file in the home directory. For
       example, with an address like jsmith+jerry@jsmachine,  the  sendmail(8)
       utility  recognizes  everything  before  the "+" as the actual username
       (jsmith) and everything after it, up to the "@" symbol, as  the  exten-
       sion (jerry) which is passed to the mail delivery agent for local use.


       The  default  value of the ForwardPath processing option in sendmail(8)
       is:

         O ForwardPath=$z/.forward.$w+$h:$z/.forward+$h:$z/.forward.$w:$z \
         /.forward



       where $z is the macro for the user's home directory, $w  is  the  macro
       for  the  local machine name and $h is the extension.  For example, for
       mail using the address, jsmith+jerry@jsmachine, the sendmail(8) utility
       checks  each  of  the four following file names, in the order given, to
       see if it exists and if it has "safe" permissions, that is,  that  nei-
       ther  the  file  nor any of its parent directories are group- or world-
       writable:

         ~jsmith/.forward.jsmachine+jerry
         ~jsmith/.forward+jerry
         ~jsmith/.forward.jsmachine
         ~jsmith/.forward



       The first file that meets the conditions is used to forward  the  mail,
       that  is,  all the entries in that file receive a copy of the mail. The
       search is then stopped.

FILES
       /etc/passwd              Password file


       /etc/nsswitch.conf       Name service switch configuration file


       /etc/mail/aliases        Mail aliases file (ascii)


       /etc/mail/aliases.db     Database of mail aliases (binary)


       /etc/mail/aliases.dir    Database of mail aliases (binary)


       /etc/mail/aliases.pag    Database of mail aliases (binary)


       /etc/mail/sendmail.cf    sendmail configuration file


       ~/.forward               Forwarding information file


ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:




       +-----------------------------+------------------------------+
       |      ATTRIBUTE TYPE         |       ATTRIBUTE VALUE        |
       +-----------------------------+------------------------------+
       |Availability                 |service/network/smtp/sendmail |
       +-----------------------------+------------------------------+

SEE ALSO
       passwd(1),   uucp(1C),   vacation(1),    ndbm(3C),    getusershell(3C),
       passwd(5), shells(5), attributes(7), newaliases(8), sendmail(8)

NOTES
       Because of restrictions in ndbm(3C), a single alias cannot contain more
       than about 1000 characters (if this format is used). The Berkeley Data-
       Base  format  does not have any such restriction. Nested aliases can be
       used to circumvent this limit.


       For aliases which result in piping to  a  program  or  concatenating  a
       file,  the  shell of the controlling user must be allowed. Which shells
       are and are not allowed are determined by getusershell(3C).



Solaris 11.4                      8 Mar 2016                        aliases(5)