@node UsecasePOP
@cindex POP3 replacement
@cindex IMAP4 replacement
@section Lightweight fast POP3/IMAP4 replacement

@ref{nncp-daemon} can be connected with @ref{nncp-caller} for a long
time -- it can create TCP connection that lasts for many hours. When
SMTP server receives mail, it will call @ref{nncp-exec} creating an
outbound encrypted packet. Daemon checks outbound directory each second
and immediately sends notification about undelivered packets to remote
side, that also downloads it at once.

There are only dozens of bytes notifying about incoming packets, dozens
of bytes telling to download those packets. Mail packets are compressed
(POP3 and IMAP4 as a rule do not). You have lightweight, compressed,
low-delay, reliable link for the mail with strong encryption and mutual
sides authentication!