MTQP, the standards-track protocol for asking a mail server what happened to a message — specified, but barely deployed.
MTQP is defined in RFC 3887 (Standards Track, 2004) and uses TCP 1038. It is a line-oriented text protocol in the style of POP3 and NNTP: a client presents an envelope identifier plus a secret from the SMTP submission, and the server returns the message's tracking history as a MIME body. It was designed to pair with the SMTP message-tracking extension, but almost no mail platform shipped it, so a listener on 1038 in the wild is far more likely to be an unrelated application or a legacy Windows RPC endpoint than a real MTQP server.
Expose with care
MTQP hands out message routing history to anyone holding the envelope ID and secret, and RFC 3887 expects TLS and authentication; a genuine MTQP server should not sit unprotected on a public IP.
$ nc -v TARGET 1038Seen this on your network? Beige Box scans your Wi-Fi and shows every open port on every device — and its Ports tool links straight back here.
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