Migrating a messaging system has three steps:
User Information— user ID, password, name, and so forth
Messages and Folders— content
Aliases and System-wide Mailing Lists— content and aliases
The techniques and methods used for migration of message and folder contents are different than those used for aliases or system mailing lists contents.
At first glance, the issue of migration of user information seems pretty trivial. However, much depends upon the format and source of the old mailing system. Some mailing systems use basic user stores such as text files, /etc/password for example. However, others might use an actual database. No problem, correct? To a point, yes, but the real issue lies in what information ...