42 Host Name Server - System Port

42 is a System Port. Transport Protocol TCP UDP , 42 Service Name name, Service Name Description: Host Name Server.

Port	Protocol	Service Name	Description	Source
42	TCP UDP	name	Host Name Server	IANA
42	TCP UDP	nameserver	Host Name Server	IANA
42	TCP UDP		ARPA Host Name Server Protocol,Official	wikipedia
42	TCP UDP		Windows Internet Name Service,Unofficial	wikipedia
42	TCP		W32.Dasher	bekkoame
42	TCP UDP	name	Host Name Server	bekkoame
42	TCP UDP	nameserver	Host Name Server	bekkoame

Port	Service Name	Description
1742	3Com-nsd	3Com-nsd
1998	x25-svc-port	cisco X.25 service (XOT)
2175	airsync	Microsoft Desktop AirSync Protocol
2189	radware-rpm-s	Secure Radware Resource Pool Manager
2600	hpstgmgr	HPSTGMGR
3004	csoftragent	Csoft Agent
3123	edix	EDI Translation Protocol
3869	ovsam-mgmt	hp OVSAM MgmtServer Disco
4234	vrml-multi-use	VRML Multi User Systems
6560		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