Active Directory Firewall Ports - Let's Try To Make This Simple

acefekay — Tue, 01 Nov 2011 05:00:00 GMT

Ace Fekay, MCT, MVP, MCITP EA, MCTS Windows 2008, Exchange 2007 & Exchange 2010, Exchange 2010 Enterprise Administrator, MCSE 2003/2000, MCSA Messaging 2003
Microsoft Certified Trainer
Microsoft MVP: Directory Services

Original Publication Date: 11/1/2011
Port Matrix Table Resized to fit in browser - 12/7/2011

RPC server not available?
Replication errors in the Event viewer?

Sound familiar?

If so, you've been succumbed to the fact and realization there are possibly necessary ports being blocked causing these errors. Whether between locations with firewall/VPN tunnel port blocks, Windows Firewall (which is usually not the culprit), or even security software or antivirus apps with some sort of "network traffic protection" feature enabled that is causing the problems.

Simply speaking, if there are replication or other AD communication problems, and you have an antivirus software installed on the endpoints or installed on all of your DCs, disable it, or better yet, uninstall it. Uninstalling it is the best bet, so you know tehre are no traces of other subcomponents that are active that may still be causing the block. If after uninstalling it, and you find replication now works, well there you have it. At that point, you'll need to contact your antivirus vendor to ask them the best way to configure it to allow AD communications and replication.

If it's not your antivirus or security app, and disabling the Windows firewall doesn't do the trick, then it's obvious it's an outside factor - your firewalls.

Also to point out, when testing for port blocks, tools such as telnet is not a good tool to test AD/DC to DC connectivity, nor is any sort of standard port scan, such as using nmap, or a simple ping, resolving with nslookup (although resolving required records is a pre-requisite), or other tools. The only reliable test is using Microsoft's PortQry, which tests specific AD ports and the ephemeral ports, and the required responses from the services on the required AD ports it specifically scans for.

Let's find out if the ports are being blocked

Now you're thinking that your network infrastructure engineers know what they're doing and opened up the necessary ports, so you're thinking, this can't be the reason? or is it? Well, let's find out. We can use PortQry to test it. And no, you don't want to use ping, nslookup, nmap or any other port scanner, because they're not designed to query the necessary AD ports to see if they are responding or not.

So let's run PortQry. If you get a "FILTERED" or "NOT LISTENING" in the results, well, that simply says the port is blocked. Download it and run it from each DC to other DCs in question, or from the bridgeheads in each site to the other bridgehead in the other site.

Knock Knock Is That Port Open?
By Mark Morowczynski [MSFT] 18 Apr 2011 3:22 PM
Quick tutorial about PortQry GUI version.
http://blogs.technet.com/b/markmoro/archive/2011/04/18/knock-knock-is-that-port-open.aspx

PortQryUI - User Interface for the PortQry Command Line Port Scanner (GUI version)
http://www.microsoft.com/download/en/details.aspx?id=24009

Download details: PortQry Command Line Port Scanner Version 2.0
http://www.microsoft.com/downloads/en/details.aspx?familyid=89811747-c74b-4638-a2d5-ac828bdc6983&displaylang=en

How to use Portqry to troubleshoot Active Directory connectivity issues
http://support.microsoft.com/kb/816103

Understanding portqry and the command's output: New features and functionality in PortQry version 2.0
http://support.microsoft.com/kb/832919

Description of the Portqry.exe command-line utility
http://support.microsoft.com/kb/310099

Portqry Remarks
http://technet.microsoft.com/en-us/library/cc759580(WS.10).aspx

"At times you may see errors such as The RPC server is unavailable or There are no more endpoints available from the endpoint mapper ..."
http://blogs.technet.com/b/askds/archive/2009/01/22/using-portqry-for-troubleshooting.aspx

Numerous ports must be opened.

That's the simplest I can put it. However, the list of ports required is long, to the dismay of network infrastructure engineering teams that must bequest ports to allow AD to communicate, replicate, etc, these ports must be opened. There really isn't much that can be done otherwise.

Here's the list:

Protocol and Port	AD and AD DS Usage	Type of traffic
TCP 25	Replication	SMTP

TCP 42	If using WINS in a domain trust scenario offering NetBIOS resolution	WINS

TCP 135	Replication	RPC, EPM

TCP 137	NetBIOS Name resolution	NetBIOS Name resolution

TCP 139	User and Computer Authentication, Replication	DFSN, NetBIOS Session Service, NetLogon

TCP and UDP 389	Directory, Replication, User and Computer Authentication, Group Policy, Trusts	LDAP

TCP 636	Directory, Replication, User and Computer Authentication, Group Policy, Trusts	LDAP SSL

TCP 3268	Directory, Replication, User and Computer Authentication, Group Policy, Trusts	LDAP GC

TCP 3269	Directory, Replication, User and Computer Authentication, Group Policy, Trusts	LDAP GC SSL

TCP and UDP 88	User and Computer Authentication, Forest Level Trusts	Kerberos

TCP and UDP 53	User and Computer Authentication, Name Resolution, Trusts	DNS

TCP and UDP 445	Replication, User and Computer Authentication, Group Policy, Trusts	SMB, CIFS, SMB2, DFSN, LSARPC, NbtSS, NetLogonR, SamR, SrvSvc

TCP 9389	AD DS Web Services	SOAP

TCP 5722	File Replication	RPC, DFSR (SYSVOL)

TCP and UDP 464	Replication, User and Computer Authentication, Trusts	Kerberos change/set password

UDP 123	Windows Time, Trusts	Windows Time

UDP 137	User and Computer Authentication	NetLogon, NetBIOS Name Resolution

UDP 138	DFS, Group Policy, NetBIOS Netlogon, Browsing	DFSN, NetLogon, NetBIOS Datagram Service

UDP 67 and UDP 2535	DHCP (Note: DHCP is not a core AD DS service but these ports may be necessary for other functions besides DHCP, such as WDS)	DHCP, MADCAP, PXE

*Ephemeral Ports:*
And most of all, the Ephemeral ports, or also known as the "service response ports," that are required for communications. These ports are dynamically created for session responses for each client that establishes a session, (no matter what the 'client' may be), and not only to Windows, but to Linux and Unix as well. See below in the references section to find out more on what 'ephemeral' means.are used only for that session. Once the session has dissolved, the ports are put back into the pool for reuse. This applies not only to Windows, but to Linux and Unix as well. See below in the references section to find out more on what 'ephemeral' means.
TCP & UDP 1025-5000	Window 2003/XP and older	Ephemeral Dynamic Service Response Ports

TCP & UDP 49152-65535	Windows 2008/Vista and newer	Ephemeral Dynamic Service Response Ports

TCP Dynamic Ephemeral	Replication, User and Computer Authentication, Group Policy, Trusts	RPC, DCOM, EPM, DRSUAPI, NetLogonR, SamR, FRS

UDP Dynamic Ephermeral	Group Policy	DCOM, RPC, EPM

*If the scenario is a Mixed-Mode NT4 & Active Directory scenario with NT4 BDCs, then the following must be opened:*
TCP & UDP 1024 - 65535	NT4 BDC to Windows 2000 or newer Domain controller PDC-E communications	RPC, LSA RPC, LDAP, LDAP SSL, LDAP GC, LDAP GC SSL, DNS, Kerberos, SMB

See, wasn't that simple?

The Short list without port explanations:

Protocol Port

TCP 25

TCP 42

TCP 135

TCP 137

TCP 139

TCP and UDP 389

TCP 636

TCP 3268

TCP 3269

TCP and UDP 88

TCP and UDP 53

TCP and UDP 445

TCP 9389

TCP 5722

TCP and UDP 464

UDP 123

UDP 137

UDP 138

UDP 67

UDP 2535

TCP & UDP 1025-5000

TCP & UDP 49152-65535

If the scenario is a Mixed-Mode NT4 & Active Directory scenario with NT4 BDCs, then the following must be opened:

TCP & UDP 1024-65535

Restricting Firewall ports

And yes, you can choose to restrict the port ranges to specific ports, and if choosing this option, you must specifically specify the correct ports for the correct service.

It depends on what ports and services you want to restrict?

1. Method 1
This is to used to set the specific AD replication port. By default it uses dynamic port to replicate data from DC in one site to another.
This is applicable for restriction AD replication to a specific port range. Procedure:
Modify registry to select a static port.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NTDS\Parameters
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Netlogon\Parameters

Restricting Active Directory replication traffic and client RPC traffic to a specific port
http://support.microsoft.com/kb/224196

2. Method 2
This is for configuring the port range(s) in the Windows Firewall.
Netsh - use the following examples to set a starting port range, and number of ports after it to use
netsh int ipv4 set dynamicport tcp start=10000 num=1000
netsh int ipv4 set dynamicport udp start=10000 num=1000

The default dynamic port range for TCP/IP has changed in Windows Vista and in Windows Server 2008
http://support.microsoft.com/kb/929851

3. Modify the registry
This is for WIndows services communications. It also affects AD communications.
HKEY_LOCAL_MACHINE\Software\Microsoft\Rpc

How to configure RPC dynamic port allocation to work with firewalls
http://support.microsoft.com/kb/154596/en-us

Here are some related links to restricting AD replication ports.

Reference thread:
http://social.technet.microsoft.com/Forums/en-US/winserverDS/thread/76e8654a-fbba-49af-b6d6-e8d9d127bf03/

RODC Firewall Port Requirements
http://technet.microsoft.com/en-us/library/dd772723(WS.10).aspx

Active Directory Replication over Firewalls
http://technet.microsoft.com/en-us/library/bb727063.aspx

RODC - "Read only Domain Controllers" have their own port requirements:

Port	Type of Traffic
UDP 53 DNS	DNS
TCP 53 DNS	DNS
TCP 135	RPC, EPM
TCP Static 53248	FRsRpc
TCP 389	LDAP

Designing RODCs in the Perimeter Network
http://technet.microsoft.com/en-us/library/dd728028(WS.10).aspx

Restricting Active Directory replication traffic and client RPC traffic to a specific port
http://support.microsoft.com/kb/224196

Good discussion on RODC and firewall ports required:
http://forums.techarena.in/active-directory/1303925.htm

Further info on how RODC authentication works will help understand the ports:
Understanding “Read Only Domain Controller” authentication
http://blogs.technet.com/b/askds/archive/2008/01/18/understanding-read-only-domain-controller-authentication.aspx

References

How to configure a firewall for domains and trusts
http://support.microsoft.com/kb/179442

Active Directory and Active Directory Domain Services Port Requirements, Updated: June 18, 2009 (includes updated new ephemeral ports for Windows Vista/2008 and newer). This also discusses RODC port requirements. You must also make sure the ephemeral ports are opened. They are:
TCP & UDP 1025-5000
TCP & UDP 49152-65535
http://technet.microsoft.com/en-us/library/dd772723(WS.10).aspx

Windows 2008, 2008 R2, Vista and Windows 7 Ephermeral Port range has changed from the ports used by Windows 2003 Windows XP, and Windows 2000. Default ephemeral (Random service dynamic response ports) are UDP 1024 - 65535 (See KB179442 below), but for Vista and Windows 2008 it's different. Their default start port range is UDP 49152 to UDP 65535 (see KB929851 below).

Quoted from KB929851 (link posted below): "To comply with Internet Assigned Numbers Authority (IANA) recommendations, Microsoft has increased the dynamic client port range for outgoing connections in Windows Vista and in Windows Server 2008. The new default start port is 49152, and the default end port is 65535. This is a change from the configuration of earlier versions of Microsoft Windows that used a default port range of 1025 through 5000."

Windows Vista, Windows 7, Windows 2008 and Windows 2008 R2 Service Response Ports (ephemeral ports) have changed.
http://support.microsoft.com/?kbid=929851

Active Directory and Firewall Ports - I found it hard to find a definitive list on the internet for what ports needed opening for Active Directory to replication between Firewalls. ...
http://geekswithblogs.net/TSCustomiser/archive/2007/05/09/112357.aspx

Active Directory Replication over Firewalls, Jan 31, 2006. (includes older pre-Windows Vista/2008 ephemeral ports)
http://technet.microsoft.com/en-us/library/bb727063.aspx

How Domains and Forests Work
Also shows a list of ports needed.
http://technet.microsoft.com/en-us/library/cc783351(v=ws.10).aspx

Paul Bergson's Blog on AD Replication and Firewall Ports
http://www.pbbergs.com/windows/articles/FirewallReplication.html

Exchange DS Access ports

Configuring an Intranet Firewall for Exchange 2003, April 14, 2006.
Protocol ports required for the intranet firewall and ports required for Active Directory and Kerberos communications
http://technet.microsoft.com/en-us/library/bb125069.aspx

Additonal Reading

Restricting Active Directory replication traffic and client RPC ...Restricting Active Directory replication traffic and client RPC traffic to a ... unique port, and you restart the Netlogon service on the domain controller. ...
http://support.microsoft.com/kb/224196

How to restrict FRS replication traffic to a specific static port - How to restrict FRS replication traffic to a specific static port ... Windows 2000-based domain controllers and servers use FRS to replicate system policy ...
http://support.microsoft.com/kb/319553

Some firewalls may reject network traffic that originates from Windows Server 2003 Service Pack 1-based or Windows Vista-based computers
This KB indicates Checkpoint firewalls having an issue with AD communications.
http://support.microsoft.com/?kbid=899148

Checkpoint Firewall and AD, DNS and RPC Communications and Replication traffic

Checkpoint firewalls have a known issue if you are running version R55 or older. You will need to make a registry entry to allows traffic to flow between the 2 sites via the vpn. The preferred solution is to upgrade the Checkpoint firewall.

More info:

Some firewalls may reject network traffic that originates from Windows Server 2003 Service Pack 1-based or Windows Vista-based computers
(This link relates to and helps resolve the Checkpoint issue)
http://support.microsoft.com/?kbid=899148

Note from one poster on the internet with a Checkpoint firewall:
For Windows 2003 R2 and non-R2 remote domain controller we added the Server2003NegotiateDisable entry in
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\Rpc

I know you've enjoyed reading this. Well, whether you did or not, at least you now know what to do to make it work.

Comments, suggestions and corrections are welcomed!

Protocol	Port
TCP	25
TCP	42
TCP	135
TCP	137
TCP	139
TCP and UDP	389
TCP	636
TCP	3268
TCP	3269
TCP and UDP	88
TCP and UDP	53
TCP and UDP	445
TCP	9389
TCP	5722
TCP and UDP	464
UDP	123
UDP	137
UDP	138
UDP	67
UDP	2535
TCP & UDP	1025-5000
TCP & UDP	49152-65535

If the scenario is a Mixed-Mode NT4 & Active Directory scenario with NT4 BDCs, then the following must be opened:
TCP & UDP	1024-65535

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