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