2 entries are registered on port 42. It is a well-known port (0–1023) — assignments here are IANA's, and a service found on one is usually the service that was assigned it.
services registered on this number
2 transports in use
entries encrypted on the wire
1 of 2 iana-registered
| port | service | proto | category | risk | views |
|---|---|---|---|---|---|
| :42 | NameServer (ARPA Hostname) | TCPUDP | Network Services | caution | 17.2k |
| :42 | WINS | TCPUDP | Network Services | caution | 16.4k |
Port 42 was historically assigned to the Host Name Server Protocol (NameServer), a part of the ARPA Network designed to manage and resolve hostnames in early networking environments, predating more modern DNS protocols. Though largely obsolete today, understanding this port helps contextualize the evolution of network naming solutions.
port 42 as NameServer (ARPA Hostname) →WINS (Windows Internet Name Service) is a Microsoft NetBIOS Name Server legacy service used primarily for name resolution on Windows networks. It enables clients to register and resolve NetBIOS names to IP addresses, facilitating easier communication in older Windows domain environments.
port 42 as WINS →The registry says what 42 is registered to. What is listening on it right now is decided by the host, and only the host can be asked. Each of these prints the process behind the socket.
ss -ltnp | grep ':42\b'lsof -nP -iTCP:42 -sTCP:LISTENnetstat -ano | findstr :42On Linux and Windows the process name comes back with the socket; on macOS lsof needs sudo to name a process that isn't yours. Match what it prints against the 2 entries above.
A port number is not a service. Anything may listen on 42 — what you actually met is decided by the host, not the registry. If a service is missing here, it belongs in the registry.
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