public-inbox-pop3d - a mostly read-only POP3 server
Old account expiry has not been implemented, but it seems to
work well with both mpop(1) and getmail(1). The strictness of
mpop was particularly helpful in ironing out bugs in our
implementation of (dreaded) message sequence numbers.
"EXPIRE 0" (RFC 2449) can theoretically save numerous "DELE"
commands, but that's untested by real-world clients. mpop
supports PIPELINING which is effective in hiding latency,
and the core networking functionality is already well-tested
from our NNTP and IMAP implementations.
Configuration requires "publicinbox.pop3state" to point to
a directory writable by the otherwise read-only daemon.
See public-inbox-pop3d(1) manpage for more usage details.