Mail Transfer Protocol

The Mail Transfer Protocol (MTP) is an obsolete network protocol used to reliably transfer mail. Request for Comments (RFC) 780,^[1] which defined this protocol, allocated Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) port 57 for MTP. This port is no longer officially allocated for this service by IANA.

Replacement

The Simple Mail Transfer Protocol (SMTP), defined in RFC 788^[2] has replaced the Mail Transfer Protocol.

See also

• List of TCP and UDP port numbers
• Simple Mail Transfer Protocol

References

1. ↑ RFC 780 Mail Transfer Protocol
2. ↑ RFC 788 Simple Mail Transfer Protocol