Aliases You may need to redirect the mail of a user to other location(s), other user(s) or even to programs. 11.. TTaasskkss For a given name, which may or may not be a real user on this machine, you are allowed to enter: AA ffiilltteerr pprrooggrraamm It is possible to "pipe" all message to a program. The program can be a binary executable, a shell script, or any shell construction such as cat >>/tmp/mail.log This command, for one, will append all incoming mail for the alias in the file /tmp/mail.log. This is the way to install mail server packages. AA lliisstt ffiillee You may want to defer the administration of a mailing list to someone without privilege. You are allowed to specify a text file holding email names. This file may belong to one user. A simple text editor is needed to manage it. OOnnee oorr sseevveerraall eemmaaiill aaddddrreessss Each email address may be simply a user name, another alias name (alias may be nested), or a full email address. You can setup simple mailing lists this way. Those features are independent. This means you can setup a filter program, a list file, and email addresses for the same alias name. 22.. PPsseeuuddoo uusseerr You might need to talk to someone in an organization without knowing his real name. Perhaps you want to talk to someone in charge of a service, for example. 22..11.. LLiisstt ooff wweellll kknnoowwnn ppsseeuuddoo--uusseerrss The _I_n_t_e_r_n_e_t has defined many pseudo-users. Here is a list of the ones you should define on your system (the mail-host server): +o hostmaster In charge of your DNS. +o postmaster This is the address to use when you need information about someone (an exact email address) or you want to signal a problem. +o usenet Used to signal a problem about news on your system. +o webmaster The person who is in charge of your Web site. 22..22.. AAlliiaasseess ffoorr aaddmmiinniissttrraattiivvee aaccccoouunnttss _L_i_n_u_x systems have several administrative accounts which receive mail. It is a pain to manually log in as one of those users just to check if there is any mail. Instead, you can redirect those accounts' mail to a real user (you?). Here is a list of those accounts: +o root +o uucp +o news 22..33.. TThhee aaddmmiinn ppsseeuuddoo--uusseerr On small sites, there may be a single administrator for the complete network. Instead of setting all those aliases to point to him, you may save time and point them to the pseudo-user "admin," which is actually an alias pointing to the administrator. This may save time. 33.. WWhheerree ttoo ddeeffiinnee aalliiaasseess Aliases are generally defined on the mail-host server of an organization. Aliases can be set up on any machine, however. 44.. MMaaiilliinngg lliisstt aaddmmiinniissttrraattoorr You can define mailing lists using aliases and alias files. This is handy and will work for small mailing lists with limited traffic (not too many new members getting in and out). With a growing mailing list, you will often get a few subscribers who have an improper email setup. Every time one member sends a message, he will get an administrative reply, stating that some unknown person did not receive email properly. This is annoying, as those members can't do anything to solve this problem. Here is a trick. If you create a mailing list, say product-list, and then create another alias, owner-product-list, which points to yourself, sendmail will automatically send error messages to you instead of to the original author of the message.