IANA is responsible for assigning port numbers to specific uses. The Well Known Ports are those in the range 0-1023. On Unix-derived operating systems, opening a port in this range to receive incoming connections requires root privileges.

See the IANA list of port assignments for a full list.

List of network protocols, by port (not exhaustive, please extend and tidy)

  • 21/tcp FTP The file transfer protocol
  • 22/tcp SSH Secure logins, file transfers(scp) and port forwarding
  • 23/tcp Telnet non secure text communications
  • 25/tcp SMTP Simple Mail Transfer Protocol (E-mail)
  • 79/tcp finger Finger
  • 80/tcp HTTP HyperText Transfer Protocol (WWW)
  • 88/tcp Kerberos Authenticating agent
  • 110/tcp POP3 Post Office Protocol (E-mail)
  • 113/tcp ident old identification server system
  • 119/tcp NNTP used for usenet newsgroups
  • 220/tcp IMAP3
  • 443/tcp HTTPS used for securely transferring web pages

(entries above 1024 should probably go on a seperate page)

  • 3306/tcp MySQL Database system
  • 6000/tcp X11 used for X-windows
  • 6667/tcp IRC, Internet Relay Chat