Registered as Janstor Secure Data — a vendor port you are unlikely to meet in the wild.
IANA assigns 5033/tcp to jtnetd-server, "Janstor Secure Data"; the UDP side is simply Reserved. There is no public specification and no widely deployed implementation, and scanners record it with a very low hit rate. If you find something on 5033 it is far more likely to be an unrelated application that chose the number than a Janstor deployment.
Expose with care
Treat it as unknown: fingerprint the listener before exposing it, since the registration tells you nothing about its authentication or encryption.
$ sudo lsof -nP -iTCP:5033 -sTCP:LISTENSeen 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.