Port 7503 services

3 entries are registered on port 750. 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.

entries
3

services registered on this number

transport
udp · tcp

2 transports in use

in transit
0/3

entries encrypted on the wire

worst risk
4/10

3 of 3 iana-registered

Services on this port

ranked by lookups
portservicerisk
:750Kerberos IVsafe
:750rfile Protocolcaution
:750loadavcaution

01Kerberos IVudp · iana-registered · risk 2/10

Kerberos version IV is an authentication protocol primarily used to verify the identities of clients and servers in distributed network environments. Operating over UDP port 750, Kerberos IV employs a ticket-based system to securely authenticate users without transmitting passwords in plaintext, enhancing overall security. Though widely influential, this older version has been mostly superseded by Kerberos V due to enhanced features and security improvements.

port 750 as Kerberos IV

02rfile Protocoltcp · iana-registered · risk 4/10

Port 750, typically associated with 'rfile', was historically used within the Kerberos authentication system developed by MIT. It served as an RPC-based frontend for remote file management, particularly for secure file transfer and operations in academic and research environments. While largely deprecated today, understanding rfile helps contextualize legacy authentication and file service protocols.

port 750 as rfile Protocol

03loadavudp · iana-registered · risk 4/10

Port 750, known as loadav, is traditionally used in UNIX environments associated with Kerberos 4's service operation. Historically, it was designated for the Kerberos 'kerberos-iv' remote authentication protocol, facilitating secure login and authentication in a distributed computing environment. Given the evolution of security practices, its use has become largely obsolete in favor of more secure protocols.

port 750 as loadav

Which one is on your host

ask the machine, not the registry

The registry says what 750 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.

linux
ss -ltnp | grep ':750\b'
macos
lsof -nP -iTCP:750 -sTCP:LISTEN
windows
netstat -ano | findstr :750

On 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 3 entries above.

A port number is not a service. Anything may listen on 750 — 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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