451 Cray Network Semaphore server - System Port

451 is a System Port. Transport Protocol TCP UDP , 451 Service Name sfs-smp-net, Service Name Description: Cray Network Semaphore server.

Port	Protocol	Service Name	Description	Source
451	TCP UDP	sfs-smp-net	Cray Network Semaphore server	IANA
451	TCP UDP	sfs-smp-net	Cray Network Semaphore server	bekkoame

Port	Service Name	Description
591	http-alt	FileMaker, Inc. - HTTP Alternate (see Port 80)
1170	atc-lm	AT+C License Manager
1572	chip-lm	Chipcom License Manager
3071	csd-mgmt-port	ContinuStor Manager Port
3164	imprs	IMPRS
3610	echonet	ECHONET
3755	sas-remote-hlp	SAS Remote Help Server
3808	sun-as-iiops-ca	Sun App Svr-IIOPClntAuth
4036	wap-push-https	WAP Push OTA-HTTP secure
5108		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