1021 RFC3692-style Experiment 1 - System Port

1021 is a System Port. Transport Protocol TCP UDP , 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
1027	6a44	IPv6 Behind NAT44 CPEs
1253	q55-pcc	q55-pcc
3555	razor	Vipul's Razor
3885	topflow-ssl	TopFlow SSL
4082	lorica-out	Lorica outside facing
5641		Unassigned
5654		Unassigned
6421	nim-wan	NIM_WAN
6895		Unassigned
7514		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