Sendmail Operation Guide

Sendmail Operation Guide

Sendmail(TM) implements a general purpose internetwork mail routing facility under the UNIX® operating system. It is not tied to any one transport protocol; instead, its function may be likened to a crossbar switch, relaying messages from one domain into another. In the process, it can do a limited amount of message header editing to put the message into a format that is appropriate for the receiving domain. All of this is done under the control of a configuration file.

Due to the requirements of flexibility for sendmail(1M), the configuration file can seem somewhat unapproachable. However, there are only a few basic configurations for most sites, for which standard configuration files have been supplied. Most other configurations can be built by adjusting an existing configuration file incrementally.

sendmail is based on the following specifications:


RFC821
Simple Mail Transport Protocol

RFC822
Internet Mail Headers Format

RFC974
MX routing

RFC1123
Internet Host Requirements

RFC1869
SMTP Service Extensions

RFC1652
SMTP 8BITMIME Extension

RFC1870
SMTP SIZE Extension

RFC1891
SMTP Delivery Status Notifications

RFC1892
Multipart/Report

RFC1893
Mail System Status Codes

RFC1894
Delivery Status Notifications

RFC1985
SMTP Service Extension for Remote Message Queue Starting

RFC2033
Local Message Transmission Protocol

RFC2034
SMTP Service Extension for Returning Enhanced Error Codes

RFC2045
MIME

RFC2476
Message Submission

RFC2554
SMTP Service Extension for Authentication
However, since sendmail is designed to work in a wider world, in many cases it can be configured to exceed these protocols. These cases are described in this topic.

Although sendmail is intended to run without the need for monitoring, it has a number of features that may be used to monitor or adjust the operation under unusual circumstances. These features are also described.

The remaining topics give brief but detailed explanations of queue file formats and a summary of the support files.


NOTE: This documentation is under modification. For the latest possible version, see ftp://ftp.cs.berkeley.edu/pub/source/sendmail/


© 2000 The Santa Cruz Operation, Inc. All rights reserved.