Provided by: nmh_1.1-release-4_i386 bug


       mh-mts - the nmh interface to the message transport system




     MMDF (any release)




       nmh  can use a wide range of message transport systems to deliver mail.
       Although the nmh administrator usually doesn’t get to choose which  MTS
       to  use  (since it’s already in place), this document briefly describes
       the interfaces.

       When communicating with SendMail, nmh always  uses  the  SMTP  to  post
       mail.   Depending  on  the  nmh  configuration, SendMail may be invoked
       directly (via a fork and an exec), or nmh may open a TCP/IP  connection
       to the SMTP server on the localhost.

       When  communicating with zmailer, the SendMail compatibility program is
       required to be installed in /usr/lib.  nmh communicates with zmailer by
       using  the  SMTP.   It  does  this  by  invoking  the /usr/lib/sendmail
       compatibility program directly, with the ‘-bs’ option.

       When communicating with MMDF, normally nmh uses the “mm_”  routines  to
       post  mail.   However,  depending on the nmh configuration, nmh instead
       may open a TCP/IP connection to the SMTP server on the localhost.

       If you are running a UNIX system with TCP/IP  networking,  then  it  is
       felt  that  the  best interface is achieved by using either SendMail or
       MMDF with the SMTP option.  This gives greater flexibility.  To  enable
       this  option  you  append the /smtp suffix to the mts option in the nmh
       configuration.  This yields two primary advantages:  First,  you  don’t
       have  to  know  where  submit  or  SendMail  live.  This means that nmh
       binaries (e.g., post ) don’t have to have this information  hard-coded,
       or  can  run  different  programs altogether; and, second, you can post
       mail with the server on different systems, so  you  don’t  need  either
       MMDF  or SendMail on your local host.  Big win in conserving cycles and
       disk space.  Since nmh supports the notion of a server  search-list  in
       this  respect, this approach can be tolerant of faults.  Be sure to set
       “servers:” as described in mh-tailor(8) if you use this option.

       There are four disadvantages to using the SMTP option: First, only UNIX
       systems  with  TCP/IP  are supported.  Second, you need to have an SMTP
       server running somewhere on any network  your  local  host  can  reach.
       Third, this bypasses any authentication mechanisms in MMDF or SendMail.
       Fourth, the file /etc/hosts is  used  for  hostname  lookups  (although
       there  is  an  exception  file).   In  response  to these disadvantages
       though: First, there’s got to be an SMTP  server  somewhere  around  if
       you’re  in  the  Internet  or  have  a local network.  Since the server
       search-list is very general, a  wide-range  of  options  are  possible.
       Second,  SMTP  should be fixed to have authentication mechanisms in it,
       like POP.  Third, nmh won’t choke on mail to hosts whose official names
       it  can’t  verify, it’ll just plug along (and besides if you enable the
       DUMB configuration options, nmh ignores  the  hosts  file  altogether).
       ^/etc/nmh/mts.conf~^nmh   mts   configuration   file  None  MMDF-II:  A
       Technical Review, Proceedings, Usenix Summer ’84 Conference
       SENDMAIL -- An Internetwork Mail Router
       mh-tailor(8), post(8) None None The /etc/nmh/mts.conf file ignores  the
       information in the MMDF-II tailoring file.