xtelld, a tiny Unix daemon that pops one-line messages onto other users' terminals.
xtell is a small message-sending tool in the spirit of write and talk: the xtell client sends a line to xtelld on another host, which displays it to the named user's terminal. The daemon defaults to TCP 4224 and is typically run from inetd; it still ships as a Debian and Ubuntu package. IANA's range assignment for 4200–4299 is unrelated, so 4224 is squatting by convention, not registration.
Do not expose
Its purpose is writing text to logged-in users' terminals from the network, with no meaningful authentication — a spam and social-engineering channel if it is reachable publicly.
$ nc -vz -w 3 TARGET 4224Seen 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.