Before getting started with SASL, you should decide which framework and mechanism you will use because it affects your installation and configuration. In order to enable SASL authentication in Postfix, you must have the Cyrus SASL library and a copy of Postfix with SASL support compiled in. Some platforms have precompiled packages available with support for SASL. If you want to use a precompiled Postfix package make sure that it specifically includes support for SASL and has the necessary SASL libraries. Furthermore, make sure that the SASL libraries were compiled with the options you need for your situation. The relevant options are described throughout the rest of this section.
Cyrus SASL library development is currently following two tracks: SASL and SASLv2. The SASL track is being phased out in favor of SASLv2. In the future, you can expect Postfix to include support for SASLv2 only. This chapter discusses SASLv2. You must have the correct combination of versions of both Postfix and the SASL libraries.
You should be able to use the latest stable version of the SASLv2 track of the Cyrus libraries. Postfix support for SASLv2 first appeared in the experimental release Version 1.1.7-20020331 and was included in the official release 2.0. It is very important that you use a version of Postfix that supports SASLv2 to follow the directions in this chapter. When the text mentions SASL, it refers to Version 2 of the library.