631 IPP (Internet Printing Protocol) - System Port

631 is a System Port. Transport Protocol TCP UDP , 631 Service Name ipp, Service Name Description: IPP (Internet Printing Protocol).

Port	Protocol	Service Name	Description	Source
631	TCP UDP	ipp	IPP (Internet Printing Protocol)	IANA
631	TCP UDP		Internet Printing Protocol (IPP),Official	wikipedia
631	TCP UDP		Common Unix Printing System (CUPS),Unofficial	wikipedia
631	TCP UDP		Mac OS X RPC-based services, Used by NetInfo, for example	Apple.com
631	TCP		Internet Printing Protocol (IPP), Mac OS X Printer Sharing, Printing to many common printers	Apple.com
631	TCP UDP	ipp	IPP (Internet Printing Protocol)	bekkoame

Port	Service Name	Description
856		Unassigned
2071	acp-port	Axon Control Protocol
2146	lv-not	Live Vault Admin Event Notification
2277	bluectrlproxy	Bt device control proxy
2490	qip-qdhcp	qip_qdhcp
3368	satvid-datalnk	Satellite Video Data Link
4344	vinainstall	VinaInstall
6498		Unassigned
6973		Unassigned
8311		Unassigned

A port is an endpoint of communication in an operating system. While the term is also used for hardware devices, in software it is a logical construct that identifies a specific process or a type of service.

Port numbers are assigned in various ways, based on three ranges: System Ports (0-1023), User Ports (1024-49151), and the Dynamic and/or Private Ports (49152-65535);

The Well Known Ports are assigned by the IANA and on most systems can only be used by system (or root) processes or by programs executed by privileged users. Ports are used in the TCP [RFC793] to name the ends of logical connections which carry long term conversations. For the purpose of providing services to unknown callers, a service contact port is defined. This list specifies the port used by the server process as its contact port. The contact port is sometimes called the "well-known port". To the extent possible, these same port assignments are used with the UDP [RFC768]. The range for well-known ports managed by the IANA is 0-1023.
DYNAMIC AND/OR PRIVATE PORTS Registered Ports are those from 1024 through 49151.
The Dynamic and/or Private Ports are those from 49152 through 65535