Running mailing lists within Postfix is fine for static lists. But lists that change frequently are better handled by a mailing-list manager (MLM). With an MLM, the administrator of the list doesn't have to manually edit the list file to add, delete, or change addresses because list members can subscribe and unsubscribe themselves. MLMs also support other features such as archiving of messages, digests of discussions, and the ability to moderate a list by allowing an administrator to review messages before they are posted to all members.
MLMs work by pointing normal Postfix aliases to commands that handle the distribution of messages and management of lists. MLMs use administrative aliases that point to programs to handle list functions such as subscribing and unsubscribing members from the list, handling bounced messages, and possibly filtering messages sent to the list. The lists themselves actually work the same way as the simple aliases from the last section. Each list has its own file to store list members, but rather than editing the file yourself, you can have the MLM automatically add and remove addresses.
The next two sections look at two popular MLMs: Majordomo and Mailman.
Majordomo is one of the more popular MLMs and has been available since the early 1990's. It offers a complete set of MLM features, and nearly all administration takes place by sending commands through email messages. Little to no intervention is required by a postmaster ...