aliases(4-BSD) MISC. REFERENCE MANUAL PAGES aliases(4-BSD)
NAME
aliases, addresses, forward - addresses and aliases for
sendmail
SYNOPSIS
/usr/ucblib/aliases
/usr/ucblib/aliases.dir
/usr/ucblib/aliases.pag
~/.forward
DESCRIPTION
These files contain mail addresses or aliases, recognized by
sendmail, for the local host:
/etc/passwd Mail addresses (usernames) of local
users.
/usr/ucblib/aliases Aliases for the local host, in ASCII
format. This file can be edited to add,
update, or delete local mail aliases.
/usr/ucblib/aliases. { dir , pag}
The aliasing information from
/usr/ucblib/aliases, in binary, dbm for-
mat for use by sendmail. The program
newaliases, which is invoked automati-
cally by sendmail, maintains these
files.
~/.forward Addresses to which a user's mail is for-
warded (see Automatic Forwarding,
below). In addition, the YP name ser-
vices aliases map mail.aliases contains
addresses and aliases available for use
across the network.
Addresses
As distributed, sendmail 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, (|), sendmail pipes the message to the
standard input of the command the bar precedes.
DARPA-standard Addresses
username@domain If domain does not contain any `.'
(dots), then it is interpreted as the name of a host in
1
aliases(4-BSD) MISC. REFERENCE MANUAL PAGES aliases(4-BSD)
the current domain. Otherwise, the message is passed
to a mailhost that determines how to get to the speci-
fied 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 Addresses
... [host!]host!username These are sometimes mistakenly
referred to as ``Usenet'' addresses. uucp 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(1M) for details.
Standard addresses are recommended.
Aliases
Local Aliases
/usr/ucblib/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 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 directs error-messages
resulting from mail to aliasname to address, instead of
back to the person who sent the message. An alias of
the form:
aliasname: :include:pathname with colons as shown,
2
aliases(4-BSD) MISC. REFERENCE MANUAL PAGES aliases(4-BSD)
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/ucblib/aliases* files on
the various hosts in a network will one day be obsolete.
Domain-wide aliases should ultimately be resolved into user-
names 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
username 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 the name of a user
on the local host, sendmail checks for a 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 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 program, user js
creates a 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 program.
FILES
/etc/passwd
/usr/ucblib/aliases
~/.forward
SEE ALSO
newaliases(1M), sendmail(1M), vacation(1), dbm(3X).
3
aliases(4-BSD) MISC. REFERENCE MANUAL PAGES aliases(4-BSD)
uucp(1C), in the User's Reference Manual.
NOTES
Because of restrictions in dbm a single alias cannot contain
more than about 1000 characters. Nested aliases can be used
to circumvent this limit.
4