| Port | Protocol | Description | Status |
| 0 | TCP | ||
| 0 | UDP | Reserved | Official |
| 1 | TCP | TCPMUX (TCP port service Multiplexer) | Official |
| 7 | TCP | ECHO protocol | Official |
| 7 | UDP | ECHO protocol | Official |
| 9 | TCP | DISCARD protocol | Official |
| 9 | UDP | DISCARD protocol | Official |
| 13 | TCP | DAYTIME protocol | Official |
| 13 | UDP | DAYTIME Protocol | Official |
| 17 | TCP | QOTD (Quote of the Day) protocol | Official |
| 19 | TCP | CHAR GEN (Character Generator) protocol | Official |
| 19 | UDP | CHAR GEN (Character Generator) protocol | Official |
| 20 | TCP | FTP (File Transfer Protocol) – data port | Official |
| 21 | TCP | FTP – control (command) port | Official |
| 22 | TCP | SSH (Secure Shell) – used for secure logins, file transfers (scp,sftp) and for forwarding | Official |
| 23 | TCP | Telnet protocol – Unencrypted text communications | Official |
| 25 | TCP | SMTP (Simple Mail Transfer Protocol) – used for sending emails | Official |
| 37 | TCP | TIME protocol | Official |
| 37 | UDP | TIME protocol | Official |
| 49 | UDP | TACACS protocol | Official |
| 53 | TCP | DNS (Domain Name Server) | Official |
| 53 | UDP | DNS – most commonly used | Official |
| 67 | UDP | BOOTP (BootStrap Protocol) server. Also used by DHCP (Dynamic Host Configuration Protocol) | Official |
| 68 | UDP | BOOTP client and DHCP | Official |
| 69 | UDP | TFTP (Trivial File Transfer Protocol) | Official |
| 70 | TCP | Gopher protocol | Official |
| 79 | TCP | Finger protocol | Official |
| 80 | TCP | HTTP (Hyper Text Transfer Protocol) | Official |
| 81 | TCP | Smoothwall Web GUI default port | Unofficial |
| 88 | TCP | Kerberos – Authenticating agent | Official |
| 109 | TCP | POP2 (Post Office Protocol version 2) Email retrieval | Official |
| 110 | TCP | POP3 (Post Office Protocol version 3) Email retrieval | Official |
| 113 | TCP | ident – Old server identification system, used by IRC to identify users | Official |
| 119 | TCP | NNTP (Network News Transfer Protocol) – Used to retrieve newsgroup messages | Official |
| 123 | UDP | NTP (Network Time Protocol) – Used for time synchronization | Official |
| 139 | TCP | NetBIOS | Official |
| 143 | TCP | IMAP4 (Internet Message Access Protocol) Used to retrieve email | Official |
| 161 | UDP | SNMP (Simple Network Management Protocol) | Official |
| 179 | TCP | BGP (Border Gateway Protocol) | Official |
| 194 | TCP | IRC (Internet Relay Chat) | Official |
| 222 | TCP | Smoothwall SSH | Unofficial |
| 389 | TCP | LDAP (Lightweight Directory Access Protocol) | Official |
| 443 | TCP | HTTPS – HTTP over SSL (encrypted transmission) | Official |
| 445 | TCP | Microsoft-DS (Active Directory, Windows shares, Sasser Worm, Agobot, Zobot Worm) | Official |
| 445 | UDP | Microsoft-DS SMB file sharing | Official |
| 465 | TCP | SMTP over SSL – Conflict with registered Cisco protocol | Unofficial/Confilict |
| 514 | UDP | syslog protocol – Used for system logging | Official |
| 540 | TCP | UUCP (Unix-to-Unix Copy Protocol) | Official |
| 542 | TCP | commerce (Commerce applications) | Official |
| 542 | UDP | commerce | Official |
| 554 | TCP | RTSP (Real Time Streaming Protocol) | Official |
| 587 | TCP | email message submission (SMTP) – RFC 2476 | Official |
| 591 | TCP | FileMaker 6.0 Web Sharing (HTTP Alternate) | Official |
| 636 | TCP | LDAP over SSL (encrypted transmission) | Official |
| 666 | TCP | id Software’s Doom Multiplayer game (number of the beast) | Official |
| 873 | TCP | rsync – File synchronization protocol | Official |
| 901 | TCP | SWAT (Samba Web Administration Tool) | Unofficial |
| 981 | TCP | SofaWare Technologies Remote HTTPS management for firewall devices running embedded Checkpoint Firewall-1 | Unofficial |
| 993 | TCP | IMAP4 over SSL (encrypted transmission) | Official |
| 995 | TCP | POP3 over SSL (encrypted transmission) | Official |
| 1080 | TCP | SOCKS proxy | Official |
| 1099 | TCP | RMI Registry | Official |
| 1099 | UDP | RMI Registry | Official |
| 1194 | UDP | OpenVPN | Official |
| 1214 | TCP | Kazaa default | Official |
| 1223 | TCP | TGP (Truly Global Protocol) | Official |
| 1337 | TCP | WASTE Encrypted File Sharing Program | Unofficial/Conflict |
| 1352 | TCP | IBM Lotus Notes/Domino RCP | Official |
| 1387 | TCP | Computer Aided Design Software Inc LM | Official |
| 1387 | UDP | Computer Aided Design Software Inc LM | Official |
| 1414 | TCP | IBM MQSeries | Official |
| 1433 | TCP | Microsoft SQL database system | Official |
| 1434 | TCP | Microsoft SQL Monitor | Official |
| 1434 | UDP | Microsoft SQL Monitor | Official |
| 1494 | TCP | Citrix MetaFrame ICA Client | Official |
| 1521 | TCP | Oracle database default listener – Conflict with registered use: nCube License Manager | Unofficial/Conflict |
| 1547 | TCP | Laplink | Official |
| 1547 | UDP | Laplink | Official |
| 1718 | TCP/UDP | H.323 Gate Discovery | |
| 1719 | TCP/UDP | H.323 Gate Stat | |
| 1720 | TCP/UDP | H.323 Host Call (VoIP) | |
| 1723 | TCP | Microsoft PPTP VPN | Official |
| 1723 | UDP | Microsoft PPTP VPN | Official |
| 1731 | TCP | Audio Call Control | |
| 1761 | TCP | Novell Zenworks Remote Control Utility – Conflict with registered use: cft-0 | Unofficial/Conflict |
| 1863 | TCP | MSN Messenger | Official |
| 1900 | UDP | Microsoft SSDP – Enabled discovery of UPnP devices | Official |
| 1984 | TCP | Big Brother – network monitoring tool | Official |
| 2000 | TCP | Cisco SCCP (Skinny) | Official |
| 2000 | UDP | Cisco SCCP (Skinny) | Official |
| 2030 | Oracle Services for Microsoft Transaction Server | Unofficial | |
| 2082 | TCP | CPanel’s default port – Conflict with registered use: Infowave Mobility Server | Unofficial/Conflict |
| 2083 | TCP | CPanel’s default port for SSL connection | Unofficial |
| 2086 | TCP | WebHost Manager’s default port – Conflict with registered use: GNUnet | Unofficial/Conflict |
| 2087 | TCP | WebHost Manager’s default port for SSL connections | Unofficial |
| 2095 | TCP | CPanel’s default port for webmail connections | Unofficial |
| 2096 | TCP | CPanel’s default port for webmail connections via SSL | Unofficial |
| 2181 | TCP | EForward – document transport system | Official |
| 2181 | UDP | EForward – document transport system | Official |
| 2222 | TCP | DirectAdmin’s default port | Unofficial |
| 2427 | UDP | Cisco MGCP | Official |
| 2447 | TCP | ovwdb – OpenView Network Node Manager (NNM) daemon | Official |
| 2447 | UDP | ovwdb – OpenView Network Node Manager (NNM) daemon | Official |
| 2517 | TCP/UDP | H.323 Annex E call signaling transport | |
| 2710 | TCP | XBT Bittorrent Tracker | Unofficial |
| 2710 | UDP | XBT Bittorrent Tracker experimental UDP tracker extension | Unofficial |
| 3050 | TCP | gds_db | Official |
| 3050 | UDP | dgs_db | Official |
| 3128 | TCP | HTTP used by web caches and Squid cache default port | Official |
| 3306 | TCP | MySQL Database System | Official |
| 3389 | TCP | Microsoft Terminal Server (RDP) officially registered as Windows Based Terminal (WBT) | Official |
| 3396 | TCP | Novell NDPS Printer Agent | Official |
| 3689 | TCP | DAAP Digital Audio Access Protocol used by Apple’s ITunes | Official |
| 3690 | TCP | Subversion version control system | Official |
| 3784 | TCP | Ventrilo VoIP program | Official |
| 3785 | UDP | Ventrilo VoIP program | Official |
| 4662 | TCP | eMule – Port often used | Unofficial |
| 4672 | UDP | eMule | Unofficial |
| 4894 | TCP | LysKOM Protocol A | Official |
| 4899 | TCP | RAdmin remote administration tool (Often trojan horse) | Official |
| 5000 | TCP | UPnP – Windows Network device interoperability; Conflict with registered use: commplex-main | Unofficial/Conflict |
| 5060 | TCP/UDP | SIP (VoIP) | |
| 5061 | TCP/UDP | SIP TLS (VoIP) | |
| 5121 | Neverwinter Nights and its mods, such as Dungeon Eternal X | Unofficial | |
| 5190 | TCP | AOL and AOL Instant Messenger | Official |
| 5222 | TCP | XMPP/Jabber – client connection | Official |
| 5223 | TCP | XMPP/Jabber – default port for SSL Client Connection | Unofficial |
| 5269 | TCP | XMPP/Jabber – server connection | Official |
| 5432 | TCP | Postgre SQL database system | Official |
| 5517 | TCP | Setiqueue Proxy server client for SETI@Home project | Unofficial |
| 5800 | TCP | VNC remote desktop protocol – for use over HTTP | Unofficial |
| 5900 | TCP | ARD/VNC remote desktop protocol – regular port | Unofficial |
| 6000 | TCP | X11 – used for X-windows | Official |
| 6112 | UDP | Blizzard’s Battle.net gaming service – Clonflict with registered use: dtspcd | Unofficial/Conflict |
| 6346 | TCP | Gnutella Filesharing | Official |
| 6347 | UDP | Gnutella | Official |
| 6600 | TCP | mpd – default port that mpd listens on | Unofficial |
| 6667 | TCP | IRC | Unofficial |
| 6668 | TCP | IRC | Unofficial |
| 6669 | TCP | IRC | Unofficial |
| 6881 | TCP | BitTorrent | Unofficial |
| 6882 | TCP | BitTorrent | Unofficial |
| 6891-6900 | TCP/UDP | MSN Messenger (File Transfer) | Official |
| 6901 | TCP/UDP | MSN Messenger (Voice) | Official |
| 7312 | UDP | Sibelius License Server | Unofficial |
| 8000 | TCP | iRDMI (Often unofficially used for internet radio streams) | Official |
| 8010 | TCP | XMPP/Jabber file transfers | Unofficial |
| 8080 | TCP | HTTP Alternate | Official |
| 8118 | TCP | Privoxy web proxy | Official |
| 11371 | OpenPGP HTTP Keyserver | Official | |
| 11576 | IPStor Server Management Communication | Official | |
| 20720 | TCP | Symantec i3 Web GUI server | Unofficial |
| 22136 | TCP | MXM endpoint administration | |
| 27000-27006 | UDP | id Sofware’s QuakeWorld Master server | Unofficial |
| 27010 | Half-Life and its mods | Unofficial | |
| 27015 | Half-Life and its mods | Unofficial | |
| 27374 | Sub7’s default port. Most script kiddies do not change. | Unofficial | |
| 27500-27900 | UDP | id Software’s QuakeWorld | Unofficial |
| 27960-27969 | UDP | id Software’s Quake III Arena and Quake III derived games | Unofficial |
| 31337 | TCP | Back Orifice – remote administration tool (often a trojan horse) (“31337” is the leet speak version of “Elite”) | Unofficial |
| 49152-65535 | TCP/UDP | Dynamic Port Range. No Official Registrations. |