NAME

aliases, addresses, forward − addresses and aliases for sendmail(8)

SYNOPSIS

/etc/passwd
/usr/lib/aliases
/usr/lib/aliases.dir
/usr/lib/aliases.pag
~/.forward

DESCRIPTION

 
These files contain mail addresses or aliases recognized by sendmail(8):

/etc/passwd Mail addresses (usernames) of local users. 

/usr/lib/aliases Local aliases in ASCII format.  This file can be edited to add, update, or delete mail aliases for the local host. 

/usr/lib/aliases.{dir,pag}
The aliasing information from /usr/lib/aliases, in binary, dbm(3X) format for use by sendmail(8). The program newaliases(8), which is invoked automatically by sendmail(8), maintains these files.

∼/.forward Addresses to which a user’s mail is forwarded (see Automatic Forwarding, below). 

In addition, the Yellow Pages 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. These are listed in the local host’s /etc/passwd file. 

•Local filenames.  When mailed to an absolute pathname, a message can be appeneded to a file. 

•Commands.  If the first character of the address is a vertical bar, (|), sendmail (8) pipes the message to the standard input of the command the bar precedes. 

•DARPA-standard mail addresses of the form:

name@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.  Top-level domains include:

.COM Commerical organizations. 

.EDU Educational organizations. 

.GOV Government organizations. 

.MIL Military organizations. 

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(1C) addresses of the form:

... [ 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 configuration file.  See the sendmail(8), and Sendmail Installation and Operation in System Administration for the Sun Workstation for details.  Standard addresses are recommended. 

ALIASES

Local Aliases

/usr/lib/aliases is formatted as a series of lines of the form

name: address [, address]

name 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.  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

directs error-messages resulting from mail to alias-name to address, instead of back to the person who sent the message. 

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. 

YP Domain Aliases

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

jsmith:js@jsmachine

then any YP client could just mail to "jsmith" and not have to remember the machine and user name for John Smith.  If a YP alias does not resolve to an address with a specific host, then the name of the YP 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 a YP client to "root@podunk-u" if the name of the YP domain is "podunk-u". 

Automatic Forwarding

When an alias (or address) is resolved to a the name of a user on the local host, sendmail checks for a .forward file in that user’s home directory.  This file can contain one or more addresses or aliases as described above; each recipient is sent a copy of the mail destined for the original user. 

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

A backslash before a username inhibits further aliasing.  For instance, to invoke the vacation(1) program, user js creates a .forward file that contains the line:

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

so that one copy of the message is sent to the user, and another is piped into the vacation(1) program.

SEE ALSO

newaliases(8), dbm(3X), sendmail(8), uucp(1C), vacation(1)

System Administration for the Sun Workstation

BUGS

Because of restrictions in dbm(3X) a single alias cannot contain more than about 1000 characters. Nested aliases can be used to circumvent this limit.

Sun Release 3.2  —  Last change: 16 July 1986