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ALIASES(5)	    UNIX Programmer's Manual	       ALIASES(5)



[1mNAME
     [0maliases, addresses, forward - addresses and aliases for
     sendmail(8)

[1mSYNOPSIS
     /etc/passwd
     /etc/aliases
     /etc/aliases.dir
     /etc/aliases.pag
     ~/.forward

DESCRIPTION
     [0mThese files contain mail addresses or aliases, recognized by
     _s_e_n_d_m_a_i_l(8), for the local host:

     /_e_t_c/_p_a_s_s_w_d	 Mail addresses (usernames) of local
			 users.
     /_e_t_c/_a_l_i_a_s_e_s	 Aliases for the local host, in ASCII
			 format.  This file can be edited to add,
			 update, or delete local mail aliases.
     /_e_t_c/_a_l_i_a_s_e_s.{_d_i_r,_p_a_g}
			 The aliasing information from
			 /_e_t_c/_a_l_i_a_s_e_s, in binary, _d_b_m(3X) format
			 for use by _s_e_n_d_m_a_i_l(8).  The program
			 _n_e_w_a_l_i_a_s_e_s(8), which is invoked automat-
			 ically by _s_e_n_d_m_a_i_l(8), maintains these
			 files.
     ~/._f_o_r_w_a_r_d          Addresses to which a user's mail is for-
			 warded (see _A_u_t_o_m_a_t_i_c _F_o_r_w_a_r_d_i_n_g,
			 below).

     In addition, the Network Information Service aliases map
     _m_a_i_l._a_l_i_a_s_e_s contains addresses and aliases available for
     use across the network.

[1mADDRESSES
     [0mAs distributed, _s_e_n_d_m_a_i_l(8) supports the following types of
     addresses:

     o+	 Local usernames. These are listed in the local host's
	 /_e_t_c/_p_a_s_s_w_d file.

     o+	 Local filenames.  When mailed to an absolute pathname, a
	 message can be appended to a file.

     o+	 Commands.  If the first character of the address is a
	 vertical bar, ([1m|[0m), _s_e_n_d_m_a_i_l(8) pipes the message to the
	 standard input of the command the bar precedes.

     o+	 DARPA-standard mail addresses of the form:

	      _n_a_m_e[1m@[0m_d_o_m_a_i_n



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ALIASES(5)	    UNIX Programmer's Manual	       ALIASES(5)



	 If _d_o_m_a_i_n does not contain any `[1m.[0m' (dots), then it is
	 interpreted as the name of a host in the current domain.
	 Otherwise, the message is passed to a _m_a_i_l_h_o_s_t 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.

     o+	 _u_u_c_p(1C) addresses of the form:

	      ... [_h_o_s_t[1m![0m]_h_o_s_t[1m![0m_u_s_e_r_n_a_m_e

	 These are sometimes mistakenly referred to as "Usenet"
	 addresses.  _u_u_c_p(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 cus-
     tomizing the _s_e_n_d_m_a_i_l configuration file.	See the
     _s_e_n_d_m_a_i_l(8), and for details.  Standard addresses are recom-
     mended.

[1mALIASES
     Local Aliases
     [0m/_e_t_c/_a_l_i_a_s_e_s is formatted as a series of lines of the form

	  _n_a_m_e[1m: [0m_a_d_d_r_e_s_s[[1m,  [0m_a_d_d_r_e_s_s]

     _n_a_m_e is the name of the alias or alias group, and _a_d_d_r_e_s_s is
     the address of a recipient in the group.  Aliases can be
     nested.  That is, an _a_d_d_r_e_s_s can be the name of another
     alias group.  Because of the way _s_e_n_d_m_a_i_l performs mapping
     from upper-case to lower-case, an _a_d_d_r_e_s_s 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 [1m# [0mare
     comments.





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     [1mSpecial Aliases

     [0mAn alias of the form:

	  [1mowner-[0m_a_l_i_a_s_n_a_m_e[1m: [0m_a_d_d_r_e_s_s

     directs error-messages resulting from mail to _a_l_i_a_s-_n_a_m_e to
     _a_d_d_r_e_s_s, instead of back to the person who sent the message.

     An alias of the form:

	  _a_l_i_a_s_n_a_m_e[1m: :include:[0m_p_a_t_h_n_a_m_e

     with colons as shown, adds the recipients listed in the file
     _p_a_t_h_n_a_m_e to the _a_l_i_a_s_n_a_m_e alias.  This allows a private list
     to be maintained separately from the aliases file.

     [1mNIS Domain Aliases
     [0mNormally, the aliases file on the master NIS server is used
     for the _m_a_i_l._a_l_i_a_s_e_s NIS map, which can be made available to
     every NIS client.	Thus, the /_e_t_c/_a_l_i_a_s_e_s* 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:

	  [1mjsmith:js@jsmachine

     [0mthen any NIS client could just mail to [1mjsmith [0mand not have
     to remember the machine and user name for John Smith.  If a
     .SM 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:

	  [1mjsmith:root

     [0msends mail on a NIS client to [1mroot@podunk-u [0mif the name of
     the NIS domain is [1mpodunk-u[0m.

     [1mAutomatic Forwarding
     [0mWhen an alias (or address) is resolved to the name of a user
     on the local host, _s_e_n_d_m_a_i_l checks for a ._f_o_r_w_a_r_d file,
     owned by the intended recipient, in that user's home direc-
     tory, 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
     ._f_o_r_w_a_r_d 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 NIS aliases.



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ALIASES(5)	    UNIX Programmer's Manual	       ALIASES(5)



     Otherwise, copies of the message may ``bounce.''  Usually,
     the solution is to change the NIS alias to direct mail to
     the proper destination.

     A backslash before a username inhibits further aliasing.
     For instance, to invoke the _v_a_c_a_t_i_o_n(1) program, user [1mjs
     [0mcreates a [1m.forward [0mfile that contains the line:

	  [1m\js, "|/usr/ucb/vacation js"

     [0mso that one copy of the message is sent to the user, and
     another is piped into the _v_a_c_a_t_i_o_n(1) program.

[1mFILES
     [0m/_e_t_c/_p_a_s_s_w_d
     /_e_t_c/_a_l_i_a_s_e_s
     ~/._f_o_r_w_a_r_d

[1mSEE ALSO
     [0m_u_u_c_p(1C), _v_a_c_a_t_i_o_n(1), _d_b_m(3X), _n_e_w_a_l_i_a_s_e_s(8), _s_e_n_d_m_a_i_l(8),

[1mBUGS
     [0mBecause of restrictions in _d_b_m(3X) a single alias cannot
     contain more than about 1000 characters.  Nested aliases can
     be used to circumvent this limit.






























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