Registered at IANA as fg-sysupdate, with no public protocol behind the name.
IANA lists 6550/tcp and 6550/udp as fg-sysupdate, assigned to an individual registrant with no reference document, no specification, and no dated registration record. There is no published protocol to describe and no widely deployed product known to bind it. If you find 6550 listening, the registry will not tell you what it is — identify the process on the host instead of trusting the service name your scanner printed.
Expose with care
An unidentified listener is an unknown attack surface. Find out what process owns it before deciding whether it belongs on the network at all.
$ sudo lsof -nP -iTCP:6550 -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.
Get Beige Box →also available as JSON · Markdown
Corrections or a missing port? Reply @rimrocksystems.