MH-MTS(8) [nmh-1.1] MH-MTS(8)
mh-mts - the nmh interface to the message transport system
MMDF (any release)
THIS IS OUT OF DATE AND NEEDS REWORKING.
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
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 compat-
ibility 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 bina-
ries (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 Techni-
cal 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.
MH.6.8 02 Feburary 2004 MH-MTS(8)