aliases(4) DG/UX R4.11MU05 aliases(4)
NAME
aliases - addresses and aliases for sendmail
DESCRIPTION
These files contain mail addresses or aliases, recognized by
sendmail(1M), for the local host:
/etc/passwd Mail addresses (user names) of local users.
/etc/aliases Aliases for the local host, in ASCII format.
This file can be edited to add, update, or delete
local mail aliases.
/etc/aliases.{dir,pag}
The aliasing information from /etc/aliases, in
binary, dbm(3X) format for use by sendmail(1M).
The program newaliases maintains these files.
~/.forward Addresses to which a user's mail is forwarded.
mail.aliases If you are running ONC/NFS, this Network
information Service (NIS) aliases map contains
addresses and aliases available for use across
the network.
As distributed, sendmail(1M) supports the following types of mail
addresses:
· Local user names. These are listed in the local host's
/etc/passwd file.
· Local file names. When mailed to an absolute path name, a
message can be appended to a file.
· Commands. If the first character of the address is a vertical
bar, (|), sendmail(1M) pipes the message to the standard input of
the command the bar precedes.
· Internet 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 that are separated by dots, with the top-level domain
on the right. Top-level domains include the following:
.com Commercial organizations.
.edu Educational organizations.
.gov Government organizations.
.mil Military groups.
.org Other organizations.
For example, the full address of K. Owen could be:
owen@cs.unc.edu
if he can be reached through the subdomain named "cs" at the
University of North Carolina.
· uucp(1) addresses of the form:
... [host!]host!username
Addresses such as these are sometimes referred to as "Usenet"
addresses. uucp(1) 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. Standard addresses are recommended.
The /etc/aliases file 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 uppercase to lowercase, an
address that is the name of another alias group must not contain any
uppercase letters.
Lines beginning with white space are treated as continuation lines
for the preceding alias. Lines beginning with # are comments.
Given an alias of the following form:
aliasname: address, address, address
an alias such as the following:
owner-aliasname: erraddress
directs error-messages resulting from mail to aliasname to
erraddress, 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.
When an alias (or address) is resolved to the name of a user on the
local host, sendmail 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. (See ONC/NFS-specific information below for additional
information specific to ONC/NFS.)
A backslash before a user name in the .forward file inhibits further
aliasing. Suppose user owen had the following .forward file:
Postmaster
\owen
Mail for owen will be redirected to Postmaster, but a copy also is
sent to owen. The sendmail program will not alias a user name
following the backslash.
DG/UX information security option information
On systems running a DG/UX information security option, when eval is
present, two features described above are disabled. These features
are:
· recognition of .forward files:
sendmail(1M) will silently ignore any .forward files.
· support of addresses which alias to commands:
sendmail(1M) generates an error if an address which resolves
to a command is used. The -on (On) sendmail(1M) option
to check aliases will flag these aliases as invalid.
ONC/NFS-specific information
If you are running ONC/NFS, the following information applies in
addition to the mail.aliases file cited above:
Normally, 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/aliases* files on the various hosts in a
network will be largely used to provide host specific aliases.
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:
mlee:ml@mlmachine
then any NIS client could just mail to mlee and not have to remember
the machine and user name for Mike Lee.
When forwarding mail between machines, be sure that the destination
machine does not return the mail to the sender through the operation
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.
FILES
/etc/passwd
/etc/aliases
/etc/aliases.dir
/etc/aliases.pag
~/.forward
SEE ALSO
uucp(1), dbm(3X), sendmail(1M).
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.
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