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
Service
TCP
UDP
Notes
SSH
22
Secure Shell *
HTTP
80
HyperText Transfer Protocol * (e.g. for web browsing).
Currently (2003-07-05) HTTP/1.1 is officially described
in RFC 2616.
81
81
* An interesting story. The name attached to this port
in the IANA list, Earl Killian, says he shouldn't be. He
says "I don't know what 81 is, or whether it is still in
use." Since Mr. Killian doesn't know what HOSTS2
is/was, and with Postel gone, I wonder if there's
anyone left in the world who knows what 81 was/is for
and who actually requested it.
HOSTS2 Name
Server
XFER Utility
82
82
* Another interesting story. The name attached to this
port in the IANA list, Thomas M. Smith of Lockheed
Martin, says Sorry... there is no publicly available
information regarding the details of the XFER Utility and
its use of tcp and udp port # 82. XFER employs a
proprietary protocol which has not been disclosed.
RPC Endpoint
Mapper
135
135
* registered as "epmap - DCE endpoint resolution".
Used by Microsoft for RPC locator service. See
additional information.
LDAP
389
389
Lightweight Directory Access Protocol *
MS NetMeeting
LDAP or ULP,
dyn >=1024,
dyn
1503, H.323
>=1024
HostCall, MS
ICCP
videoconferencing
Timbuktu
1417-1420
407
remote control *
SLP
427
427
Service Location Protocol * Used by MacOS and
NetWare.
HTTPs
443
LPD / printer
515
secure HTTP (SSL) *
515
printing * LPD stands for Line Printer Daemon. Also see
printing section.
ULP
522
522
User Location Protocol (Microsoft) *
AppleTalk Filing
Protocol (AFP)
548
548
*
QuickTime 4
RTSP
RTP-QT4
streaming audio, video *
RTSP
554
Real Time Streaming Protocol *. Currently (2003-07-05)
described in RFC 2326.
NNTPs
563
secure NNTP news (SSL) *
Internet Printing
Protocol (IPP)
631
631
print remotely to any IPP enabled printer through the
Internet * The Common Unix Printing System (CUPS) is
based on IPP. Also see printing section.
LDAPs
636
636
secure LDAP * (LDAP protocol over TLS/SSL)
Doom
666
666
network game *
Remotely Possible
(ControlIT)
799
remote control. CA ControlIT support.
SOCKS
1080
internet proxy *. Also used by Trojans.
Kazaa
1214
1214
Lotus Notes Domino 1352
peer-to-peer file sharing *
*
VocalTec Internet
Phone
1490, 6670,
25793
22555
Citrix ICA
1494, dyn
>=1023
1604, dyn
remote application access *
>=1023
Virtual Places
1533
Xing StreamWorks
videoconferencing *
conferencing *, also see VP voice
1558
streaming video *
Novell GroupWise
(Remote Client)
1677
1677
group collaboration * NOTE: Other features of
GroupWise use many other ports.
H.323 Host Call
1720
1720
H.323 host call *
virtual private network (VPN) * Note PPTP also uses the
GRE protocol. However Microsoft says in Understanding
PPTP: "PPTP can be used with most firewalls and
routers by enabling traffic destined for port 1723 to be
routed through the firewall or router."
PPTP
1723
MS ICCP
1731
1731
MS NetShow
1755
1755, dyn
>=1024 streaming video *
<=5000
MSN Messenger
1863
Netopia netOctopus 1917, 1921
audio call control (Microsoft) *
instant messenging *. NOTE: For detailed info on ports
for file transfers, voice and video, see the Windows and
MSN Messenger section below.
1917
network management *
ICU II
2000-2003
videoconferencing. NOTE: security risk on TCP port
50000
iSpQ
2000-2003
videoconferencing. Note: support docs are inconsistent
on what ports are required
glimpseserver
2001
search engine
Distributed.Net
RC5/DES
2064
distributed computation
SoulSeek
2234, 5534
2234,
5534
file sharing
Microsoft DirectX
2300-2400,
gaming (DirectPlay)
47624
7
networked multiplayer games, * only 47624 is
2300-2400 registered as "Direct Play Server", if needed also see
MSN Gaming Zone
Microsoft DirectX
gaming (DirectPlay)
8
23022400,
6073
networked multiplayer games, * only 6073 is registered
as DirectPlay8, if needed also see MSN Gaming Zone
MADCAP - Multicast 2535
2535
* defined in RFC 2730 - Multicast Address Dynamic
Address Dynamic
Client Allocation
Protocol
Client Allocation Protocol (MADCAP). Also used by
Trojans.
Netrek
2592
network game *
URBISNET
2745
2745
* Alex Tronin reports was used for Urbis geolocation
service... now not operational, but may be revived. Also
used by Trojans.
Borland Interbase
database
3050
3050
* gds_db. See CERT Advisory CA-2001-01 for potential
security risk.
squid
3128
3130
web proxy cache. Also used by Trojans.
iSNS
3205
3205
* Internet Storage Name Service, see iSCSI section
iSCSI default port
3260
3260
* SCSI over IP, see iSCSI section
Windows Remote
Desktop Protocol
(RDP)
3389
NetworkLens SSL
Event
3410
* registered as ms-wbt-server. RDP 5.1 is the current
version. See below for more information. Remote
Desktop Web Connection also uses HTTP.
3410
Virtual Places Voice 3450, 8000Chat
9000
* Also used by Trojans.
voice chat, also see Virtual Places
Apple iTunes music
3689
sharing (DAAP)
3689
Digital Audio Access Protocol *
Mirabilis ICQ
4000
locator, chat (note: see newer AOL ICQ)
dyn >=1024
4000, 6112Blizzard / Battle.net
6119
Abacast
4000-4100,
4500, 90009100
GlobalChat client,
server
4020
PGPfone
4000,
network gaming - support (captured 2001-11-11),
6112-6119 proxy and firewall info
peer-to-peer audio and video streaming. NOTE: This
software will create OUTGOING streams to other users
if it can.
4020
chat rooms, used to be called ichat
4747
secure phone
PlayLink
4747, 4748,
10090
6144
online games
radmin
4899
4899
remote control *
Yahoo Messenger 5000-5001
Voice Chat
GnomeMeeting
5000-5010 voice chat
H.323
5000audio and videoconference. 5000-5003 is RTP and
HostCall,
5003,
RTCP range for this app.
30000-30010 5010-5013
Yahoo Messenger 5050
messages
SIP
5060
messaging. NOTE: It will try ports 5050, 80, any port.
5060
Session Initiation Protocol *. For audio and video.
Currently (2003-07-05) see RFCs 3261, 3262, 3263,
3264, 3265
SIP, RTP- audio and video conferencing. May also need iChat local
iChatAV
port.
Apple iChat AV
Yahoo Messenger 5100
Webcams
video
AOL Instant
Messenger (AIM)
5190
5190
America OnLine * Also used by Apple iChat (in AIM
compatibility mode).
AIM Video IM
1024-5000 ?
1024-5000 video chat. It is unclear from their FAQ whether you
?
need to open both TCP and UDP ports.
AOL ICQ
5190, dyn
>=1024
AOL
5190-5193
5190-5193 America OnLine *
XMPP / Jabber
5222, 5269
5222,
5269
messaging
* Extensible Messaging and Presence Protocol. Also see
Using Jabber behind firewalls. Defined by XMPP specs
(RFCs now issued), specs created by IETF group.
iChat local traffic
5298
5298
Some Rendezvous thing.
Multicast DNS
5353
5353
* Mac OS X 10.2: About Multicast DNS. Related to
Zeroconf which Apple has implemented as Rendezvous.
(Note: the regular Domain Name Service port is 53.)
Dialpad.com
5354, 7175,
8680-8890,
9000, 94509460
dyn
>=1024
telephony
HotLine
5500-5503
SGI ESP HTTP
5554
5554
* SGI Embedded Support Partner (ESP) web server.
Also used by Trojans, see SGI Security Advisory
20040501-01-I.
InfoSeek Personal
Agent
5555
5555
* I don't know if InfoSeek Personal Agent exists
anymore. This port is commonly used by HP OpenView
Storage Data Protector (formerly HP OmniBack).
pcAnywhere
5631
5632
remote control *
peer-to-peer filesharing.
eShare Chat Server 5760
eShare Web Tour
5761
eShare Admin
Server
5764
VNC
5800+, 5900+
remote control
GNUtella
6346, 6347
6346,
6347
Netscape
Conference
H.323
HostCall,
6498, 6502
2327
audioconferencing
Danware NetOp
Remote Control
6502
6502
remote control
common IRC
6665-6669
Net2Phone
CommCenter
selected
BitTorrent
6881-6889,
6969
RTP-QT4
VDOLive
7000
peer-to-peer file sharing *
Internet Relay Chat *
6801,
selected
telephony, admin should select one TCP and UDP port
in the range 1-3000. Same ports are used by Yahoo
Messenger - PC-to-Phone.
distributed data download, newer versions TCP 68816999. Alternate FAQ link.
6970-6999
Realtime Transport Protocol. (These ports are
specifically for the Apple QT4 version.)
userspecified
streaming video
Real Audio & Video RTSP, 7070
6970-7170 streaming audio and video
CU-SeeMe,
Enhanced CUSM
7648, 7649,
LDAP
76487652,
24032
videoconferencing
common HTTP
8000, 8001,
8080
Apache JServ
8007
Protocol v12 (ajp12)
8007
(default port) See Workers HowTo for config info.
Apache JServ
8009
Protocol v13 (ajp13)
8009
(default port) e.g. Apache mod_jk Tomcat connector
using ajp13. See Workers HowTo for config info.
PDL datastream
9100
9100
printing * PDL is Page Description Language. Used
commonly by HP printers and by Apple. Also see
printing section.
MonkeyCom
9898
9898
* video-chat, also used by Trojans
9943,
9945,
56768
videoconferencing
iVisit
The Palace
9992-9997
common Palace
9998
NDMP
10000
10000
Network Data Management Protocol *. Used for storage
backup. Also used by Trojans.
Amanda
10080
10080
backup software *. Also used by Trojans.
Yahoo Games
11999
network games
12345
12345
network chat supporting multiple access methods *
Appears mostly used in Japan. There are many other
applications calling themselves "italk". TrendMicro
OfficeScan antivirus also uses this port. Commonly used
by Trojans.
1638416403
Used by Apple iChat AV.
1638432767
Realtime Transport Protocol. RTP in general is
described in RFC 3550. This range is not registered (it
never could be, being so broad) but it seems to be
somewhat common. See Are there specific ports
assigned to RTP?
14238
data synchronization
Italk
RTP-iChatAV
RTP
Palm Computing
Network Hotsync
14237
Liquid Audio
18888
FreeTel
9992-9997 chat environment *
chat environment
streaming audio
2130021303
audioconferencing
VocalTec Internet
Conference
22555
22555
audio & document conferencing *
Quake
26000
26000
network game *
MSN Gaming Zone
28800-29100
2880029100
network gaming (zone.com, zone.msn.com), also see
DirectPlay 7 and DirectPlay 8
Sygate Manager
39213
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?
Service
Ports
Game
5001-5010
Login
7775-7777
Patch
8888
Notes
overlaps with common HTTP port
UO Messenger 8800-8900 includes port 8866 which is also used by Trojan
Patch
9999
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
Service
TCP
Windows Messenger - voice (computer to
phone)
UDP
2001-2120,
6801, 6901
MSN Messenger - file transfers
68916900
MSN Messenger - voice communications
(computer to computer)
6901
Notes
from Q324214. NOTE: 6801 is
Net2Phone.
from Q278887. Allows up to 10
simultaneous transfers.
6901
from Q278887
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.
TCP
Port
Service
SMTP - Simple
Mail Transfer
Protocol
Notes
25
* As part of the anti-spam best practices, you should block this outgoing for
any machine that doesn't need to send email directly.
SMTPs - secure
SMTP
465
Port 465 shows up Appendix A of the 1996 non-standard standard The SSL
Protocol Version 3.0 as "Simple Mail Transfer Protocol with SSL". Unfortunately,
it's not registered for SMTPs, it's registered for URD - "URL Rendesvous
Directory for SSM" by Cisco. The recommended approach, at least for
authentication, is to use START TLS encryption on submission port 587.
(SMTP email)
submission
587
* See RFC 2476 - Message Submission.
POP2 - Post
109
Office Protocol 2
* obsolete
POP3 - Post
110
Office Protocol 3
*
POP3s - secure
POP3
995
* Full description is "pop3 protocol over TLS/SSL (was spop3)".
IMAP3 Interactive Mail
Access Protocol
v3
220
* obsolete
IMAP4 - Internet
Message Access 143
Protocol 4
* Also referred to by version as IMAP4.
IMAPs - secure
IMAP
* Full description is "imap4 protocol over TLS/SSL". Use 993 instead of TCP port
585 "imap4-ssl", which is deprecated.
993
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.
Service
TCP
QuickTime Conferencing (MovieTalk) 458
UDP
458, dyn >= 7000
Notes
videoconferencing *
Apple VideoPhone
MovieTalk MovieTalk
Connectix VideoPhone
MovieTalk MovieTalk, dyn >=1024, 4242 videoconferencing
videoconferencing *
Netscape CoolTalk
6499, 6500 13000
videoconferencing
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:
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PracticallyNetworked:
o Handling Special Applications
o Special Applications - Opening Ports
o Special Applications - Port List
HomeNetHelp:
o Explaining DMZs and Port Forwarding
o Port list for running a server through a router
o 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:
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microsoft.public.msn.messenger: Google Groups or newsreader
microsoft.public.windowsxp.messenger: Google Groups or newsreader
microsoft.public.internet.mschat: Google Groups or newsreader
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microsoft.public.internet.netmeeting: Google Groups or newsreader
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