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 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

iSCSI

iSCSI is specified in RFC 3720 - Internet Small Computer Systems Interface.

The well-known user TCP port number for iSCSI connections assigned by IANA is 3260 and this is the default iSCSI port. Implementations needing a system TCP port number may use port 860, the port assigned by IANA as the iSCSI system port; however in order to use port 860, it MUST be explicitly specified - implementations MUST NOT default to use of port 860, as 3260 is the only allowed default.

Also associated with iSCSI is iSNS, Internet Storage Name Service, on port 3205.

These services essentially open up your storage to the Internet in ways even more deep than CIFS, NFS and other file-level sharing services. Therefore you should be very careful about security and may want to block these ports completely, or tightly limit access to them.

Printing

There are several port numbers that may be involved with printing.

Print Server Port Numbers is a useful guide.

The three main ones are LPD ("printer") on port 515, IPP on 631, and PDL-datastream on 9100.

Apple MacOS X Rendezvous Printing (PDF) will discover printers that are advertising their services. They give the example

For example, the Apple LaserWriter 8500 would register the following services,
assuming the default domain is "local."

Apple LaserWriter 8500._printer._tcp.local.        Port 515
Apple LaserWriter 8500._ipp._tcp.local.            Port 631
Apple LaserWriter 8500._pdl-datastream._tcp.local. Port 9100

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: PalTalk Networking Support.

Ultima Online

Information from What are the port numbers I need to play UO behind a firewall or proxy server?

Windows and MSN Messenger Application

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

• For file transfer or voice chat ports and NAT information for MSN Messenger 3 see MS Support article Q278887.
• Microsoft Knowledge Base Article Q324214 - You cannot make phone calls or start voice or video conversations with Windows Messenger
• Windows Messenger 5.0 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 July 17, 2002

For Windows Messenger in a non-UPnP environment, unfortunately Microsoft requires dynamic UDP ports across a very wide range. This is a tremendous security risk. Try to establish a UPnP environment if possible. Nevertheless, here is what they say To support [audio and video] in both directions through the firewall, all UDP ports between 5004 and 65535 must be opened to allow signaling (SIP) and media streams (RTP) to traverse the firewall.

Also note: I don't know how much information for WINDOWS Messenger applies to MSN Messenger and vice versa. I also don't know how much information for MSN Messenger Windows version applies to MSN Messenger Mac version. And last but not least, there are multiple different versions of Messenger, which may differ in various ways.

Email Ports

Email is sent around the Internet mainly from server to server using SMTP. Once delivered, clients may access it in a variety of ways, including POP3 and IMAP. This section DOES NOT cover Microsoft Exchange or other proprietary mail protocols.

The major upcoming change to email is the use of TCP port 587 "submission" for email, as defined in section 3.1 of RFC 2476 - Message Submission. This is planned to replace the traditional use of TCP port 25, SMTP.

3.1. Submission Identification

Port 587 is reserved for email message submission as specified in this document. Messages received on this port are defined to be submissions. The protocol used is ESMTP [SMTP-MTA, ESMTP], with additional restrictions as specified here.

While most email clients and servers can be configured to use port 587 instead of 25, there are cases where this is not possible or convenient. A site MAY choose to use port 25 for message submission, by designating some hosts to be MSAs and others to be MTAs.

This initiative is being promoted by, amongst others, the Anti-Spam Technical Alliance. See Anti-Spam Technical Alliance Technology and Policy Proposal, Version 1.0, 22 June 2004 (PDF)

We further recommend that SMTP authentication be implemented on the standard Mail Submission Port, port 587, and that ISPs encourage their customers to switch their mail client software (for example, MS Outlook, Eudora, and so on) to this port. Using this port will provide seamless connectivity that does not depend on if a network allows port 25 traffic.

In addition to SMTP, the other main email protocols are POP3 and IMAP, these are protocols for email clients to access their mailboxes. There are many other topics that are outside the scope of this page. For example, email addresses are described in RFC 2822 (obsoletes RFC 822), and SMTP authentication is covered in RFC 2554 - SMTP Service Extension for Authentication. Transport Layer Security (TLS) is covered in RFC 2246 - The TLS Protocol Version 1.0. SMTP over TLS is covered in RFC 3207 - SMTP Service Extension for Secure SMTP over Transport Layer Security.

The Network Sorcery RFC Sourcebook entry for SMTP also links to many relevant RFCs that cover the details of the protocol itself.

Oracle Database TCP/IP Ports

I have a separate page for Oracle ports.

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 (585K)

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
• UpOneLevel Network Port listing
• Techeez Port Search

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

This section discusses specific port information related to Microsoft or provided by them. If you are looking for information about Windows firewalls, including XP Service Pack 2, see the Windows Security Software and Built-in Windows Firewalls sections of my Trojan TCP/IP Ports page.

Microsoft has announced a new Windows Firewall in Windows XP Service Pack 2, it replaces the Internet Connection Firewall (ICF) in previous versions of Windows.

• MS KB 842242 - Some programs seem to stop working after you install Windows XP Service Pack 2 has a section "Identifying and opening ports" and also a fairly extensive list of ports in "Programs that may require you to open ports manually", although for all of the games it says "see the documentation" in the Ports column which is not exactly helpful information.
• How to Open Ports in the Windows XP Internet Connection Firewall has a list of ports followed by instructions
• Port Requirements for the Microsoft Windows Server System (KB 832017)
• 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
• Active Directory Replication over Firewalls
• 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

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.

Although it doesn't give any port numbers, you may find Rendezvous service types being used by Mac OS X useful.

Novell (NetWare)

• Novell Documentation: NetWare 6 - Port Number Assignments
• Matrix of Ports used in NetWare 6 - TID 10065719
• TCP/IP Port Numbers used by Novell Products - TID 10014320 (NetWare 5.0 and earlier)

IBM (WebSphere)

• Firewall Port Assignments in WebSphere Application Server V5

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.

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.

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

Tim Williams' list of Ports Used by Computer Games has lots of good info.

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