The default plaintext IRC port — where clients connect to chat networks without TLS.
An IRC client opens 6667, sends NICK and USER, and the server answers with a numeric welcome burst and the MOTD; from there everything is line-based text terminated by CRLF, as defined in RFC 1459 and its successors. It is the default port in essentially every IRC client, inside IANA's 6665-6669 ircu block, and RFC 7194 names 6697 as its TLS counterpart. It still shows up on scans of chat networks, of bouncers, and of IRC-controlled malware that never moved off the classic port.
Expose with care
Everything is cleartext, including the password you send to NickServ. Fine for a public chat server that offers TLS on 6697 alongside; never the right choice for anything private.
$ printf 'QUIT\r\n' | nc -v -w 5 TARGET 6667Seen 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.