46 MPM [default send] - System Port

46 is a System Port. Transport Protocol TCP UDP , 46 Service Name mpm-snd, Service Name Description: MPM [default send].

Port	Protocol	Service Name	Description	Source
46	TCP UDP	mpm-snd	MPM [default send]	IANA
46	TCP UDP	mpm-snd	MPM [default send]	bekkoame

Port	Service Name	Description
3757	grf-port	GRF Server Port
4360	matrix-vnet	Matrix VNet Communication Protocol IANA assigned this well-formed service name as a replacement for "matrix_vnet".
4821		Unassigned
5225	hp-server	HP Server
7400	rtps-discovery	RTPS Discovery
7536		Unassigned
7938		Unassigned
8822		Unassigned
11293		Unassigned
14024		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