Registered to "LL Surfup HTTP" and effectively never seen in the wild.
IANA lists 1183 for both TCP and UDP under the service name llsurfup-http, described only as "LL Surfup HTTP", with no assignee recorded and no public protocol specification. There is no maintained product, RFC, or open-source implementation behind the name that can be pointed at today. If 1183 is listening on a host you administer, the registration tells you nothing useful — identify the process locally rather than trusting the registry name.
Expose with care
An unexpected listener here is an unidentified service, not a known protocol; find the owning process before deciding anything about exposure.
$ sudo lsof -nP -iTCP:1183 -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.