558 SDNSKMP - System Port | Service Name:sdnskmp

558 is a System Port. Transport Protocol TCP UDP , 558 Service Name sdnskmp, Service Name Description: SDNSKMP.

Port	Protocol	Service Name	Description	Source
558	TCP UDP	sdnskmp	SDNSKMP	IANA
558	TCP UDP	sdnskmp	SDNSKMP	bekkoame

Port	Service Name	Description
708		Unassigned
2125	lockstep	LOCKSTEP
2348	redstorm-info	Information to query for game status IANA assigned this well-formed service name as a replacement for "redstorm_info".
2464	direcpc-si	DirecPC SI
2642	tragic	Tragic
4045	npp	Network Paging Protocol
4294	vrml-multi-use	VRML Multi User Systems
5605	a4-sdunode	A4-SDUNode
5971		Unassigned
6246		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