Managing IMAP

Open Source Server Implementations

For nearly a decade, there have been only two appreciable open source IMAP servers: the University of Washington’s IMAP server and Carnegie Mellon University’s Cyrus IMAP server. Both are robust, time- and user-tested servers with an install base to rival any commercial alternative.

We will go into more detail in later chapters about the interesting histories and specific features of each server, but let’s take a brief look at them for the time being.

University of Washington IMAP Server

The University of Washington server is the reference implementation of IMAP. It was written by Mark Crispin, the inventor of IMAP. It was started in 1988 at Stanford University as a C rewrite of the original Interlisp client and DEC-20 assembly language server. When Crispin changed jobs for the University of Washington late in 1988, the IMAP project went with him.

The University of Washington IMAP server strives for compatibility with existing Unix systems. If you’ve stored your mail in a given format on a Unix system over the course of the past few decades, chances are that the UW server can read that format out of the box.

The UW server has a number of interesting experimental extensions, such as multiple append and server-based sorting and threading. The UW server also supports an extensive list of international character sets.

The UW server is very modular—it is easy to add support for another mailbox format or SASL authenticator by writing a code ...