Unassigned at IANA, inside the empty 7904-7912 block — no standard service claims it.
IANA leaves 7904 through 7912 unassigned, so 7911 has no registered name; Nmap likewise records it as unknown, open on roughly 0.04% of scanned hosts. The next registration up is 7913 (qo-secure). Nothing common binds 7911 by default, so a listener is a local choice.
Expose with care
No registration, no expectations — find the process behind it and rate that service rather than the number.
$ sudo lsof -nP -iTCP:7911 -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.