FreeSWITCH's Event Socket — a text console that controls the whole telephony switch.
IANA registers 8021 to Intuit as intu-ec-client, but the port's real fame is FreeSWITCH: the stock event_socket.conf.xml sets listen-port to 8021, and mod_event_socket is how dialplan applications, click-to-call scripts and monitoring tools drive the switch. Nmap also records 8021 as a common FTP proxy port, a much older convention that pairs it with 21. On a VoIP host, assume FreeSWITCH.
Do not expose
The Event Socket is full administrative control of the PBX — originate calls, read channel variables, reload configuration — behind a single password. It is meant for loopback or a tightly ACLed management network.
$ nc -vz -w 3 TARGET 8021Seen 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.