523 IBM-DB2 - System Port | Service Name:ibm-db2

523 is a System Port. Transport Protocol TCP UDP , 523 Service Name ibm-db2, Service Name Description: IBM-DB2.

Port	Protocol	Service Name	Description	Source
523	TCP UDP	ibm-db2	IBM-DB2	IANA
523	TCP UDP	ibm-db2	IBM-DB2	bekkoame

Port	Service Name	Description
873	rsync	rsync
1498	sybase-sqlany	Sybase SQL Any
2037	applus	APplus Application Server
3388	cbserver	CB Server
5020	zenginkyo-1	zenginkyo-1
5173		Unassigned
5523		Unassigned
5668		Unassigned
5861		Unassigned
5894		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