POP3 Server Stub is designed to distribute test e-mail messages - the way they look in various email client software and how they are passed through different filtering programs. You can change not only the body of the message but also the headers. Using it you can avoid SMTP and mailbox related hassle, and at the same time distribute the message to many email programs simultaneously. It also may be useful for those who develop POP3 client software. The program listens on some TCP port and supports POP3 protocol (RFC 1939).