An Apple SASL authentication port registered in 2003 and absent from modern macOS.
IANA lists 3659 as apple-sasl, registered by David M. O'Rourke of Apple in January 2003, from the era when Mac OS X Server ran an Open Directory Password Server offering SASL authentication to its mail, file, and directory services. Apple never published a wire specification for it, macOS Server itself is discontinued, and the port does not appear in Apple's current list of ports used by Apple software. A listener here on a modern Mac is something else that took a free port.
Do not expose
Anything genuinely serving SASL is an authentication endpoint; there is no documented transport security here, so keep it internal and prefer a current, documented auth service.
$ nmap -Pn -sV -p 3659 TARGETSeen 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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