Ports for Internet Services :

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• Table of Ports for Internet Services
• Official TCP/IP Port List (IANA assigned port numbers)
• Searchable Port Lists
• Understanding TCP/IP
• Articles and Related Resources
• Network Protocols
• Related Info: Trojan Ports, Firewall Books
• Questions

Any Port in a Datastorm

It seems like every day there is a new Internet service that uses some new set of poorly-documented, unregistered ports. I created this page to gather together all the information I could find about the ports used by these new services, for use by firewall administrators and other network monitors.

• "dyn" in the ports field denotes dynamically allocated port(s), usually in the range >=1024 <=65535
• A name in the ports field (e.g. LDAP) indicates that service is also required
• A plus sign + in the ports field indicates the service may use a series of ports starting at the specified one
• An asterisk * in the Notes field indicates that the ports are IANA registered

When a specific port is registered it is usually assigned for both TCP and UDP even though only one or the other may be required. Where possible I have only shown the required ones.

This is not intended to list old, well-documented services such as telnet, FTP, SMTP etc. You can find these in the IANA list.

You may contact me by email with any suggestions or corrections, or post a message to the TCP/IP Ports discussion.

Ports for Internet Services

Napster

After examining Napster, I decided it was such a complex protocol that it deserved its own section. The first thing to be aware of is that there are two versions of Napster. The "original" flavor is what most people will be interested in. This is the full music file-sharing service. This original service provided by Napster.com has now been shut down. Napster.com will be providing a new service with much more controlled music sharing. However, the original protocol lives on, and the protocol has been analyzed so that people could write compatible applications for many different operating systems.

There is information on the protocol (and how to get it through your firewall) from:

• Microsoft Support Q275236
• opennap.sourceforge.net
• david.weekly.org

Here is a summary of the TCP ports it uses. I have put the notation (primary) after the main port, if more than one port is listed.

• metaserver / redirector: 8875
• directory servers: 4444, 5555, 6666, 7777, 8888 (primary)
• client: 6600 to 6699 (primary)

PalTalk

PalTalk is another messy service that uses many ports, more than I want to summarize here. Visit their support page: Getting PalTalk To Work With Your Firewall Or Network.

Obsolete Services

Apple released QuickTime 4 some time ago. I am unsure of the status of their older QuickTime Conferencing (MovieTalk) protocol. All of the applications that supported it (Connectix VideoPhone, Apple VideoPhone, Netscape CoolTalk, QuickTime TV) are no longer supported and the QuickTime Conferencing website is gone.

Official TCP/IP Port Assignments

• IANA - TCP/IP Port Assignments (553K)

Also note, although you will sometimes see mention of RFC 1700 "Assigned Numbers" (dated October 1994) it was long ago obsoleted by the official IANA list. Do not use RFC 1700 as a reference. This fact is now officially documented by RFC 3232 "Assigned Numbers: RFC 1700 is Replaced by an On-line Database".

Network Sorcery lists the IANA TCP/UDP Ports with links to pages describing some protocols in detail, as part of its incredibly useful RFC Sourcebook.

Searchable Port Lists

These cover registered, unregistered, and trojan ports - note that many ports have legitimate, required uses, even though people have also used them as trojan ports.

• Andrew Daviel's Network Service Query is a very nice port metasearch engine
• Tantalo.net Ports database
• Neohapsis Ports List
• PC Flank Ports Database
• portsdb.org Ports Database
• Snort Ports Database
• SecurityStats.Com TCP/UDP Port Search
• Dave's Port Lookup lists registered services along with known trojans
• WeetHet in English or in Dutch lists both registered and trojan ports

Understanding TCP/IP

The IBM RedBooks are an amazing resource for many technical topics. They have a TCP/IP Tutorial and Technical Overview available as HTML or 7.7 MB PDF.

Cisco also provides excellent information online. Internet Protocols is just one section of their Internetworking Technology Handbook.

There is information on IP (the protocol on which TCP and UDP are built) in Internet Core Protocols: The Definitive Guide Sample Chapter 2: The Internet Protocol [IP].

Articles and Related Resources

Windows

• TCP and UDP Port Assignments (Windows 2000 Server - Resource Kits - TCP/IP Core Networking Guide - Appendix C)
• NetBIOS Over TCP/IP [original page removed; using archive.org version]
• Firewall Information - Windows Media Technologies
• Microsoft has provided a good list of Windows NT, Terminal Server, and Microsoft Exchange Services Use TCP/IP Ports
• TCP/UDP Ports Used By Exchange 2000 Server
• TCP, UDP, and RPC Ports Used by MSMQ (Microsoft Message Queue Server)
• A List of the Windows 2000 Domain Controller Default Ports

More information about Windows Remote Desktop Protocol (RDP)

As indicated in the RDP section above, this protocol uses a registered TCP port. It is used for XP Pro Remote Desktop and XP Remote Assistance (read Administering Remote Assistance for a very good overview of firewall, NAT and blocking issues). Also used for WinNT4 Terminal Server, Win2000 Terminal Services, and Win .NET Server 2003 Terminal Server.

Windows Remote Procedure Call (RPC) and Distributed COM (DCOM)

In some cases, Microsoft uses port 135 as an RPC Endpoint Mapper. Runs as RPCSS on (some versions of?) Windows. This is a sort of "RPC directory" service which can be used to lookup what ports other services are running on. For some additional information, see Windows 2000 Network Architecture: Remote Procedure Call and NT Gatekeeper: RPC and Firewall Configuration.

MS-RPC on port 135 is required for some Exchange Server and Active Directory communications. See e.g. TCP Ports and Microsoft Exchange: In-depth Discussion and Restricting Active Directory Replication Traffic to a Specific Port.
However this port also poses a security risk, as indicated in the NET SEND section of my broadband security page.

UPDATE 2003-08-13: Also see the Blaster Worm section for information about this additional security risk.

Additional information:

• Using Distributed COM with Firewalls
• RPC and Firewall Configuration
  Sidebar: RPC Dynamic Port Allocation

Windows and MSN Messenger Application

A related note: the Messenger Service that runs at the Windows SERVICE level is different from the Windows or MSN Messenger application. For information about the Messenger APPLICATION see

• Windows Messenger in Windows XP: Working with Firewalls and Network Address Translation Devices.
• Microsoft Support WebCast - Microsoft Windows Messenger for Windows XP: New Features, Common Issues, and Troubleshooting

Mac

OpenDoor (makers of DoorStop) have a nice list of MacOS-related ports, with hyperlinks to relevant information.

Apple support has provided a list of "Well Known" TCP and UDP Ports Used By Apple Software Products.

Novell (NetWare)

TCP/IP Port Numbers used by Novell Products

IP Telephony / Voice over IP (VoIP) / H.323 / SIP / RTP

Some applications that use H.323 include: ohphone, ohphoneX, ...

Getting H.323 audio/video conferencing through firewalls is particularly problematic. I have used Google cache to rescue an Intel document The Problems and Pitfalls of Getting H.323 Safely Through Firewalls. Note in particular that RTCP (Real Time Control Protocol) has no fixed port, an RTCP session is paired with an RTP session, if you have an RTP stream on even numbered UDP port x, RTCP is on x + 1.

• IP Ports and Protocols used by H.323 Devices
• Cisco: IP Telephony / VoIP Traversal of NAT and Firewall

General

The white paper Cisco PIX Firewall and Stateful Firewall Security contains some useful information about the ports and connection protocols for VDOnet, CU-SeeMe, and RealAudio.

Ed Bott's article Block those ports! contains some useful information, and also a kind review of this web page. He also links to my page from the about.com Windows and Internet Security Information page on TCP and UDP ports.

You can check out Internet Firewalls: Frequently Asked Questions. As of this writing it was last updated 2000/12/01 but it still has lots of good information.

You may also find useful a list of ports specified in ipmasq format (actually it gives you sets of rules you can use with either ipchains or ipfwadm).

NetGear's Applications Port List lists a lot of games.

By popular request: a page on Blocking Chat Programs.

More and more good resources are becoming available, particularly for people with home networks. If you haven't found what you were looking for here, you can try:

• PracticallyNetworked:
  • Handling Special Applications
  • Special Applications - Opening Ports
  • Special Applications - Port List
• HomeNetHelp:
  • Explaining DMZs and Port Forwarding
  • Port list for running a server through a router
  • Port list for running a game server through a router or firewall

Network Protocols

Note that certain services such as IPSec and Microsoft's PPTP use non-TCP/UDP protocols so they may be more complicated to use. In particular, PPTP uses GRE (protocol 47) and IPSec uses ESP (protocol 50) and AH (protocol 51). Protocol numbers are not the same as port numbers. IANA maintains the Assigned Internet Protocol Numbers.

Related Information: Trojan TCP/IP Ports, Free Firewall Book

Those of you concerned with Internet security may wish to also check out my companion page, Trojan TCP/IP Ports for a list of ports used by trojan horse and backdoor programs. Also I have a link to firewall books there (including a free book).

Questions

If you have questions, comments or suggestions specifically about this page or TCP/IP ports then you can email me or use my QuickTopic: Discuss TCP/IP Ports.

For firewall questions I suggest the USENET group comp.security.firewalls via groups.google.com or your newsreader.

If your question is Microsoft-specific, you may want to try the USENET microsoft.public groups, in particular:

• microsoft.public.msn.messenger: Google Groups or newsreader
• microsoft.public.windowsxp.messenger: Google Groups or newsreader
• microsoft.public.internet.mschat: Google Groups or newsreader
• microsoft.public.internet.netmeeting: Google Groups or newsreader

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