Port 1021 RFC3692-style Experiment 1 - System Port

Port 1021 is a System Port. Transport Protocol TCP UDP , Port 1021 Service Name exp1, Service Name Description: RFC3692-style Experiment 1.

Port	Protocol	Service Name	Description	Source
1021	TCP UDP	exp1	RFC3692-style Experiment 1	IANA
1021	SCTP	exp1	RFC3692-style Experiment 1	IANA
1021	DCCP	exp1	RFC3692-style Experiment 1	IANA
1021	TCP UDP		Mac OS X RPC-based services, Used by NetInfo, for example	Apple.com
1021	TCP		Webus	bekkoame

Port	Service Name	Description
1087	cplscrambler-in	CPL Scrambler Internal
1443	ies-lm	Integrated Engineering Software
2006	invokator
2083	radsec	Secure Radius Service
2123	gtp-control	GTP-Control Plane (3GPP)
2484	ttc-ssl	Oracle TTC SSL
3050	gds-db	gds_db IANA assigned this well-formed service name as a replacement for "gds_db".
3736	rs-rmi	RealSpace RMI
5341		Unassigned
6428		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