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Annotation of coherent/a/usr/man/COHERENT/mail, revision 1.1.1.1

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                      2: 
                      3: mail                         Overview                        mail
                      4: 
                      5: 
                      6: 
                      7: 
                      8: Electronic mail system
                      9: 
                     10: 
                     11: The  COHERENT system  includes a  full-featured,  UNIX-style mail
                     12: system.  It  consists of a  number of commands  and files through
                     13: which you  can describe potential  recipients of mail,  either on
                     14: your  system  or other  systems,  and send  mail  to them  either
                     15: directly or  via UUCP.  This article describes  the design of the
                     16: COHERENT mail system,  and introduces the commands and files that
                     17: compose it.
                     18: 
                     19: ***** Structure of the COHERENT Mail System *****
                     20: 
                     21: The  COHERENT mail  system has three  major components:  the _u_s_e_r
                     22: _a_g_e_n_t  (i.e., mmaaiill);  the _r_o_u_t_i_n_g _a_g_e_n_t  (the commands  ssmmaaiill and
                     23: rrmmaaiill); and the delivery agents (the commands llmmaaiill and uuuuxx).
                     24: 
                     25: The user agent collects messages from the user and reads messages
                     26: from  a  user's  mailbox.  It  hands  to  the  routing agent  for
                     27: delivery any messages it receives from the user.
                     28: 
                     29: The routing  agents decode addresses and decide  how to deliver a
                     30: message.  They  are the only  components of the  mail system that
                     31: must run sseettuuiidd to assume the privilege of the superuser rroooott.
                     32: 
                     33: The delivery agents move messages to their destination.
                     34: 
                     35: The  local delivery  agent,  llmmaaiill, places  messages into  users'
                     36: mailboxes.   To  discourage  mail  forging,  llmmaaiill does  not  use
                     37: sseettuuiidd. It  must be run by a privileged  user (generally rroooott) to
                     38: write into all mail boxes.  As a rule, llmmaaiill is invoked only by a
                     39: routing agent.
                     40: 
                     41: The UUCP delivery agent, uuuuxx, queues messages for transmission to
                     42: remote systems.   It uses sseettuuiidd  to assume the  identity of user
                     43: uuuuccpp in order to  write into the necessary spool directories.  It
                     44: has long  been trivial to  forge messages to  remote systems with
                     45: uuuuxx; keep this in mind if you plan to use electronic mail for any
                     46: kind of authorization system.
                     47: 
                     48: ssmmaaiill  looks up  each _u_s_e_r in  file /uussrr/lliibb/mmaaiill/aalliiaasseess.  If it
                     49: finds a match, it uses the matched name in place of _u_s_e_r. If _u_s_e_r
                     50: is of the form
                     51: 
                     52: 
                     53:         _s_y_s!_u_s_e_r
                     54: 
                     55: 
                     56: or
                     57: 
                     58: 
                     59: 
                     60: 
                     61: 
                     62: 
                     63: 
                     64: COHERENT Lexicon                                           Page 1
                     65: 
                     66: 
                     67: 
                     68: 
                     69: mail                         Overview                        mail
                     70: 
                     71: 
                     72: 
                     73:         _s_y_s! ... !_u_s_e_r
                     74: 
                     75: 
                     76: or
                     77: 
                     78: 
                     79:         _u_s_e_r@_s_y_s[._d_o_m_a_i_n]
                     80: 
                     81: 
                     82: it  is  treated  as a  remote  destination.   ssmmaaiill then  invokes
                     83: command uuuuxx  to pass the message to  _s_y_s, whose responsibility it
                     84: becomes to pass the message to _u_s_e_r.
                     85: 
                     86: If   ssmmaaiill   finds   no   match  in   /uussrr/lliibb/mmaaiill/aalliiaasseess,   or
                     87: $HHOOMMEE/.aalliiaasseess, however, it attempts to look up each _u_s_e_r in file
                     88: /eettcc/ppaasssswwdd, to see if this is a local user.  If it does not find
                     89: _u_s_e_r  in this  file, ssmmaaiill  mails  an error  message back  to the
                     90: sender.   If, however,  it  does find  _u_s_e_r in  this file,  ssmmaaiill
                     91: checks   file   $HHOOMMEE/.ffoorrwwaarrdd   for  any   possible   forwarding
                     92: instructions.  If  this file is absent,  ssmmaaiill passes the message
                     93: to   llmmaaiill.   llmmaaiill    writes   the   message   into   the   file
                     94: /uussrr/ssppooooll/mmaaiill/_u_s_e_r.    This   file   is   called   the   user's
                     95: ``mailbox''.  Note  that _u_s_e_r owns  this file, and  can therefore
                     96: permit or deny access to her mail by other users.
                     97: 
                     98: ***** Files *****
                     99: 
                    100: $HHOOMMEE/ddeeaadd.lleetttteerr -- Message that mmaaiill could not send
                    101: $HHOOMMEE/.aalliiaasseess -- Personal mail alias file for outgoing mail
                    102: $HHOOMMEE/.ffoorrwwaarrdd -- Forwarding instructions for inbound mail
                    103: /eettcc/ppaasssswwdd -- User identities
                    104: /ttmmpp/mmaaiill* -- Temporary and lock files
                    105: /uussrr/lliibb/mmaaiill/aalliiaasseess -- Aliases of users
                    106: /uussrr/lliibb/mmaaiill/ffuullllnnaammeess -- Short full name aliases of users
                    107: /uussrr/lliibb/mmaaiill/ppaatthhss -- Mail routing control file
                    108: /uussrr/ssppooooll/mmaaiill -- Mailbox directory, filed by user name
                    109: 
                    110: ***** See Also *****
                    111: 
                    112: aalliiaasseess, ccoommmmaannddss, mmaaiill, mmkkffnnaammeess, mmssgg, nnppttxx, ppaatthhss, uuuuxx
                    113: 
                    114: ***** Notes *****
                    115: 
                    116: To  mail a  file  to another  user, use  the shell's  redirection
                    117: operator `<'.  For example, the command
                    118: 
                    119: 
                    120:         mail stephen <bug.report
                    121: 
                    122: 
                    123: mails file bbuugg.rreeppoorrtt to  user sstteepphheenn. The file will be prefixed
                    124: with  your address,  and suffixed  with your  mail ``signature'',
                    125: should you have one.
                    126: 
                    127: 
                    128: 
                    129: 
                    130: COHERENT Lexicon                                           Page 2
                    131: 
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