174 MAILQ - System Port | Service Name:mailq

174 is a System Port. Transport Protocol TCP UDP , 174 Service Name mailq, Service Name Description: MAILQ.

Port	Protocol	Service Name	Description	Source
174	TCP UDP	mailq	MAILQ	IANA
174	TCP UDP	mailq	MAILQ	bekkoame

Port	Service Name	Description
462	datasurfsrvsec	DataRampSrvSec
568	ms-shuttle	microsoft shuttle
1031		Reserved
1172	dnap	DNA Protocol
2086	gnunet	GNUnet
2088	ip-blf	IP Busy Lamp Field
6195		Unassigned
6673	vision-elmd	vision_elmd IANA assigned this well-formed service name as a replacement for "vision_elmd".
6816		Unassigned
7343	swx	The Swiss Exchange

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