Registered as "disclose" for campaign contribution disclosures; no public implementation exists.
IANA registers TCP and UDP 667 as "disclose", described as campaign contribution disclosures for SDR Technologies. It is one of the more specific and less used registrations in the system port range, with no published protocol specification and no software you can point at. Anything listening on 667 in practice is unrelated to the registration.
Do not expose
Effectively an unused system port, so a listener is unaccounted-for software — investigate it rather than expose it.
$ nc -vz -w 3 TARGET 667Seen 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.