---
name: "mh-mts"
section: "8"
platform: "linux"
package: "nmh"
version: "1.2-3"
release: "Debian 5.0 (Lenny)"
platforms: ["linux"]
url: "https://new.carta.tech/mh-mts"
---

# mh-mts(8)

the nmh interface to the message transport system

## NAME

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

## SYNOPSIS

SendMail

Zmailer

MMDF (any release)

stand-alone

## DESCRIPTION

THIS IS OUT OF DATE AND NEEDS REWORKING.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 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)](/post/8.md) None None The /etc/nmh/mts.conf file ignores the information in the *MMDF-II* tailoring file.