Internet Printing Protocol (IPP) – port 631

To submit a print job or to retrieve status information from the printer, an HTTP POST request is sent to the IPP server listening on port 631/tcp. A famous open-source IPP implementation is CUPS, which is the default printing system in many Linux distributions and OS X.

• 631 – Internet Printing Protocol(IPP) (HackTricks)

Nmap scripts

nmap -sV -p 631 --script=cups* $IP