638 mcns-sec - System Port | Service Name:mcns-sec

638 is a System Port. Transport Protocol TCP UDP , 638 Service Name mcns-sec, Service Name Description: mcns-sec.

Port	Protocol	Service Name	Description	Source
638	TCP UDP	mcns-sec	mcns-sec	IANA
638	TCP UDP		Mac OS X RPC-based services, Used by NetInfo, for example	Apple.com
638	TCP UDP	mcns-sec	mcns-sec	bekkoame

Port	Service Name	Description
1829	optika-emedia	Optika eMedia
2858	ecnp	ECNP
3260	iscsi-target	iSCSI port
5269	xmpp-server	XMPP Server Connection
6293		Unassigned
6567		Reserved
6829		Unassigned
9055		Unassigned
9177		Unassigned
9394		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