Sendmail Operation Guide

Sendmail Operation Guide

Sendmail

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
RFC1123: Internet Host Requirements
RFC2045: MIME
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

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.

``Basic installation'' describes how to do a basic sendmail installation.
``Normal operations'' supplies the day-to-day information you should have to maintain your mail system. If you have a relatively normal site, these two topics should contain sufficient information for you to install sendmail and keep it happy.
``Arguments'' describes some parameters that may be safely modified.
``Tuning'' has information regarding the setting of configuration parameters.
``The configuration file'' contains the main body of information about the configuration file, and is for people who must write their own configuration file.
``Other configuration'' describes configuration that can be done at compile time.

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/