The protocol is incredibly simple. It works with numbered responses to a handful of commands. The RFC makes it fairly easy with, albeit incomplete, examples. About the only thing tricky is, for some unknown reason, there are gaps in the message number base. To start, you must find a real message number with repeated use of the STAT command. You can’t simply seek approximately to where you want to start, and use NEXT. It is a minor goof in the design of the protocol.

The protocol is slow, requiring a NEXT, HEAD and BODY command to retrieve each message individually.