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. Registered port numbers are those in the range 1024-49151. Port numbers in the range 49152-65535 are private or dynamic ports, not used by any defined application.

IANA does not enforce this; it is simply a set of recommended uses. Sometimes ports may be used for different applications or protocols than their official IANA designation. This misuse may, for example, be by a Trojan horse. Or it may be a common program that you use every day, but that never got an IANA registered port or port range.

ICANN formed a contract with the US government (http://www.icann.org/general/iana-contract-21mar01.htm) on March 21, 2001, and now performs the IANA's function.

See the IANA list of port assignments (http://www.iana.org/assignments/port-numbers) for a full list.

0 to 1023

• 9/tcp Discard Protocol
• 9/udp Discard Protocol
• 13/tcp Daytime Protocol
• 17/tcp Quote of the Day
• 20/tcp FTP The file transfer protocol - data
• 21/tcp FTP The file transfer protocol - control
• 22/tcp SSH Secure logins, file transfers (scp, sftp) and port forwarding
• 23/tcp Telnet non secure text communications
• 25/tcp SMTP Simple Mail Transfer Protocol (E-mail)
• 53/tcp DNS Domain Name Server
• 53/udp DNS
• 67/udp BOOTP BootStrap Protocol (Server) Also used by DHCP Dynamic Host Configuration Protocol
• 68/udp BOOTP BootStrap Protocol (Client) Also used by DHCP Dynamic Host Configuration Protocol
• 69/udp TFTP Trivial File Transfer Protocol
• 70/tcp Gopher
• 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
• 143/tcp IMAP4 Internet Message Access Protocol (E-mail)
• 443/tcp HTTPS used for securely transferring web pages
• 445/tcp Microsoft-DS (Active Directory, Windows shares, Sasser-worm)
• 445/udp Microsoft-DS
• 591/tcp FileMaker 6.0 Web Sharing (HTTP Alternate, see port 80)
• 993/tcp IMAP4 Internet Message Access Protocol (E-mail) over SSL
• 995/tcp POP3 Post Office Protocol (E-mail) over SSL

1024 to 49151

• 1080/tcp SOCKS Proxy
• 1352/tcp IBM Lotus Notes/Domino RCP
• 1433/tcp Microsoft-SQL-Server
• 1434/tcp Microsoft-SQL-Monitor
• 1434/udp Microsoft-SQL-Monitor
• 1984/tcp Big Brother
• 3128/tcp HTTP used by web caches and the default port for the Squid cache
• 3306/tcp MySQL Database system
• 3389/tcp Microsoft Terminal Server (RDP)
• 5190/tcp AOL and AOL Instant Messenger
• 6000/tcp X11 used for X-windows
• 6667/tcp IRC, Internet Relay Chat
• 8000/tcp iRDMI. Often mistakenly used instead of port 8080.
• 8080/tcp HTTP Alternate (http-alt) or WWW caching service (web cache). Often used when running a second web server on the same machine, for proxy and caching server, or for running a Web server as a non-root user. See also Port 80. Tomcat also uses this as its default port.
• 8118/tcp privoxy http filtering proxy service

49152 to 65535

Unregistered Ports

These are ports that may be in common use, but that are not formally registered with IANA. Where the use conflicts with a registered use, the notation CONFLICT is used.

• 1337/tcp WASTE Encrypted File Sharing Program
• 1521/tcp Oracle database default listener (CONFLICT with registered use: nCube License Manager)
• 2082/tcp CPanel's default port (CONFLICT with registered use: Infowave Mobility Server)
• 2086/tcp Web Host Manager's default port (CONFLICT with registered use: GNUnet)
• 5000/tcp Universal Plug and Play Windows network device interoperability (CONFLICT with registered use: commplex-main)
• 5432/tcp Postgres Database system
• 5800/tcp VNC remote desktop protocol (for use over HTTP)
• 5900/tcp VNC remote desktop protocol (regular port)
• 6881/tcp BitTorrent port often used
• 6969/tcp BitTorrent tracker port (CONFLICT with registered use: acmsoda)
• 31337/tcp Back Orifice Remote administration tool (often Trojan horse)

External links

• Official IANA list (http://www.iana.org/assignments/port-numbers) (also linked above)
• list of selected/nonstandard TCP/IP ports and related information (http://www.akerman.ca/port-table.html)
• ports.tantalo.net
• Kurt Seifried's ports list (http://www.seifried.org/security/ports/)
• iss.net Port Knowledgebase (http://www.iss.net/security_center/advice/Exploits/Ports/)