net-mail
Perdition is a fully featured POP3 and IMAP4 proxy server.
It is able to handle both SSL and non-SSL connections and redirect users
to a real-server based on a database lookup. Perdition supports modular
based database access. ODBC, MySQL, PostgreSQL, GDBM, POSIX Regular
Expression and NIS modules ship with the distribution. The API for
modules is open allowing abitary modules to be written to allow access
to any data store.