Mail server

A Mail server is a computer server which provides SMTP, POP3 and/or IMAP services. This enables the sending and receiving of email messages.

There are several programs that run on mail servers:

Table of contents

1 SMTP 2 POP/IMAP 3 Mail filtering

SMTP

• Sendmail - The most versatile, but the one with the most cryptic configuration file. It has had a history of security holes, including the Morris worm.
• Postfix - By Wietse venema. This MTA is designed for security, with several separate programs each of which does a task.
• qmail - By Dan Bernstein. Similar in design to Postfix. Additionally the programs run as different user IDs.
• Exim
• Courier

• UW IMAP - Uses mbox format.
• Courier IMAP - Uses Maildir format, which is much faster and requires no file locking.