For example, the full address of John Smith could be:
js@jsmachine.Podunk-U.EDUif he uses the machine named jsmachine at Podunk University.
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) manual page for details. Standard addresses are recommended.
/etc/mail/aliases is formatted as a series of lines of
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 a hash sign (#) are comments.
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:
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.
Normally, the aliases maps on the master NIS server are used for the mail.aliases NIS map, which can be made available to every NIS client. With NIS, the local /etc/mail/aliases file is consulted first, then the maps on the NIS server. 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@jsmachinethen any NIS client could just mail to jsmith and not have to remember the machine and username for John Smith. If a 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:rootsends mail on a NIS client to root@podunk-u if the name of the NIS domain is podunk-u.