Unassigned at IANA; a port that lives mostly in old intrusion-detection signature lists.
IANA lists 6707-6713 as Unassigned, and nmap's service database records no name for 6711. It has no registered protocol and no current product default. Its reputation comes from late-1990s Windows backdoor lore, where ports just above 6700 appear in old firewall and IDS rule sets, but there is no authoritative registration or vendor documentation to point at — so treat any listener here as unidentified software rather than as a confirmed anything.
Expose with care
Nothing legitimate is expected here. An open 6711 on a Windows host is worth running down to a named process.
$ sudo lsof -nP -iTCP:6711 -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.