Port Number Reference

Local processing

Local reference of selected common ports, protocols and service conventions

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Standards, sources and review dates

IANA service names and ports · curated reference · Reviewed 2026-10-19
Common ports are a curated selection, not an authoritative full registry or proof of which service is running. Review interval: 30 days.

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104 ports

Port	Protocol	Service	Description	Category
Port	Protocol	Service	Description	Category
`20`	TCP	FTP-Data	File Transfer Protocol (data transfer)	File Transfer
`21`	TCP	FTP	File Transfer Protocol (control)	File Transfer
`22`	TCP	SSH	Secure Shell - encrypted remote access and file transfer	Remote Access
`23`	TCP	Telnet	Unencrypted text communications (legacy)	Remote Access
`25`	TCP	SMTP	Simple Mail Transfer Protocol - email sending	Email
`53`	TCP/UDP	DNS	Domain Name System - translates domain names to IPs	Network Infrastructure
`67`	UDP	DHCP Server	Dynamic Host Configuration Protocol (server)	Network Infrastructure
`68`	UDP	DHCP Client	Dynamic Host Configuration Protocol (client)	Network Infrastructure
`69`	UDP	TFTP	Trivial File Transfer Protocol	File Transfer
`80`	TCP	HTTP	Hypertext Transfer Protocol - unencrypted web traffic	Web
`110`	TCP	POP3	Post Office Protocol v3 - email retrieval	Email
`119`	TCP	NNTP	Network News Transfer Protocol - Usenet	News
`123`	UDP	NTP	Network Time Protocol - time synchronization	Network Infrastructure
`137`	UDP	NetBIOS-NS	NetBIOS Name Service	Windows Networking
`138`	UDP	NetBIOS-DGM	NetBIOS Datagram Service	Windows Networking
`139`	TCP	NetBIOS-SSN	NetBIOS Session Service	Windows Networking
`143`	TCP	IMAP	Internet Message Access Protocol - email retrieval	Email
`161`	UDP	SNMP	Simple Network Management Protocol	Network Management
`162`	UDP	SNMP-Trap	SNMP Trap (notifications)	Network Management
`179`	TCP	BGP	Border Gateway Protocol - internet routing	Network Infrastructure

Port Number Ranges

Well-Known Ports	`0 - 1023` System ports; binding restrictions depend on the operating system and configuration.	Registered Ports	`1024 - 49151` User ports; consult IANA for individual registrations.	Dynamic/Ephemeral	`49152 - 65535` Dynamic/private ports; IANA does not assign these to services.