The remote-configuration port on Lantronix serial-to-Ethernet device servers — read/write access to the whole device config.
Lantronix device servers such as the XPort and UDS families listen on 30718, which the vendor documentation writes as hex 77FEh, so that DeviceInstaller, the embedded Web Manager, and custom programs can read and write the unit's setup records remotely. The XPort user guide lists it among the reserved ports, ships it enabled by default, and defaults its access mode to Read & Write. IANA has 30718 inside an unassigned block, so nothing else claims the number; a scan hit here is almost always an embedded serial console or industrial gateway. Nmap sees it far more often on UDP than on most high ports, which matches a discovery protocol that answers broadcasts.
Do not expose
This is an unauthenticated-by-default configuration plane for an embedded device; disable it (Security Settings > Disable Port 77FEh) or keep it strictly on a management segment, never on a public IP.
$ nc -vz -w 3 TARGET 30718Seen 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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