This is  POP3Lite, a flexible, RFC 1939  compliant Post Office
Protocol 3 daemon.

It  implements   everything  mentioned  in   the  RFC  (either
natively, or via modules), and  some other things that are not
strictly  POP3  related  capabilities  (such as  modules,  PAM
support, SQL configuration, etc).

- George Reid
greid@ukug.uk.freebsd.org