730 IBM NetView DM/6000 send/tcp - System Port

730 is a System Port. Transport Protocol TCP UDP , 730 Service Name netviewdm2, Service Name Description: IBM NetView DM/6000 send/tcp.

Port	Protocol	Service Name	Description	Source
730	TCP UDP	netviewdm2	IBM NetView DM/6000 send/tcp	IANA
730	TCP UDP		Mac OS X RPC-based services, Used by NetInfo, for example	Apple.com
730	TCP UDP	netviewdm2	IBM NetView DM/6000 send tcp	bekkoame

Port	Service Name	Description
905		Unassigned
1026	cap	Calendar Access Protocol
2749	fjippol-cnsl
2894	abacus-remote	ABACUS-REMOTE
3018	srvc-registry	Service Registry IANA assigned this well-formed service name as a replacement for "srvc_registry".
3133	prism-deploy	Prism Deploy User Port
4755		Unassigned
5212		Unassigned
5318	pkix-cmc	PKIX Certificate Management using CMS (CMC)
5335		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