The middle of IANA's 3367-3371 satellite-video reservation — a registration with no public protocol behind it.
3370 falls inside the satvid-datalnk range IANA assigned to Scott Engel for a "Satellite Video Data Link". There is no RFC, no published wire format, and no widely deployed implementation. In practice the port is free real estate: application servers, test harnesses, and ad-hoc proxies land on it because nothing else claims it. Treat a listener here as unidentified until you have matched it to a process.
Expose with care
Any exposure decision depends entirely on what is actually bound — identify the process first, because the registration tells you nothing about it.
$ ss -lntp 'sport = :3370'Seen 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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Corrections or a missing port? Reply @rimrocksystems.