Domain Controller Multiple NIC DNS problem

hi everybody
I have a domain controller with two IP addresses. It adds both of them
automatically to DNS. Is there any way possible that let me choose which one
of these ip addresses should be added into DNS and prevent the other one to
be added automatically ?

Do NOT multihome a domain controller:

Multihomed DCs, DNS, RRAS servers.
++++++++++++++++++++++++++++++++++++++++++++++++++ +++++
++++++++++++++++++++++++++++++++++++++++++++++++++ +++++
Below are the manual steps in more detail, which I had outlined in the above
paragraph:

Honestly, multi-homed DCs are not recommended because of the associated issues
that can occur, as you've encountered. We usually recommend purchasing an
inexpensive Linksys, DLink, etc, Cable/DSL router to perform NAT for you,
take out the extra NIC off the DC, but still let the DC handle DHCP (and
not the router).

Little background on AD and DNS:
First, just to get this out of the way, if you have your ISP's DNS addresses
in your IP configuration (DCs and clients), they need to be REMOVED.

If the ISP's DNS is in there, this will cause additional problems.

Also, AD registers certain records in DNS in the form of SRV records that
signify AD's resource and service locations. When there are multiple NICs,
each NIC registers. IF a client, or another DC queries DNS for this DC, it
may get the wrong record. One factor controlling this is Round Robin. If
a DC or client on another subnet that the DC is not configured on queries
for it, Round Robin will kick in offering one or the other. If the wrong
one gets offered, it may not have a route to it. On the other hand, Subnetmask
Priortization will ensure a querying client will get an IP that corresponds
to the subnet it's on, which will work. To insure everything works, stick
with one NIC.

Since this DC is multi-homed, it requires additional configuration to prevent
the public interface addresses from being registered in DNS. This creates
a problem for internal clients locating AD to authenticate and find other
services and resources such as the Global Catalog, file sharing and the SYSVOL
DFS share and can cause GPO errors with Userenv 1000 events to be logged,
authenticating to shares and printers, logging on takes forever, among numerous
other issues.

But if you like, there are some registry changes to eliminate the registration
of the external NIC. Here's the whole list of manual steps to follow.

But believe me, it's much easier to just get a separate NAT device or multihome
a non-DC then having to alter the DC. - Good luck!

1. Insure that all the NICS only point to your internal DNS server(s) only
and none others, such as your ISP's DNS servers' IP addresses.

2. In Network & Dialup properties, Advanced Menu item, Advanced Settings,
move the internal NIC (the network that AD is on) to the top of the binding
order (top of the list).

3. Disable the ability for the outer NIC to register. The procedure, as
mentioned, involves identifying the outer NIC's GUID number. This link will
show you how:
246804 - How to Enable-Disable Windows 2000 Dynamic DNS Registrations (per
NIC too):
http://support.microsoft.com/?id=246804

4. Disable NetBIOS on the outside NIC. That is performed by choosing to
disable NetBIOS in IP Properties, Advanced, and you will find that under the
"WINS" tab. You may want to look at step #3 in the article to show you how
to disable NetBIOS on the RRAS interfaces if this is a RRAS server.
296379 - How to Disable NetBIOS on an Incoming Remote Access Interface
[Registry Entry]:
http://support.microsoft.com/?id=296379

Note: A standard Windows service, called the "Browser service", provides
the list of machines, workgroup and domain names that you see in "My Network
Places" (or the legacy term "Network Neighborhood"). The Browser service
relies on the NetBIOS service. One major requirement of NetBIOS service is
a machine can only have one name to one IP address. It's sort of a fingerprint.
You can't have two brothers named Darrell. A multihomed machine will cause
duplicate name errors on itself because Windows sees itself with the same
name in the Browse List (My Network Places), but with different IPs. You
can only have one, hence the error generated.

5. Disable the "File and Print Service" and disable the "MS Client Service"
on the outer NIC. That is done in NIC properties by unchecking the respective
service under the general properties page. If you need these services on
the outside NIC (which is unlikely), which allow other machines to connect
to your machine for accessing resource on your machine (shared folders, printers,
etc.), then you will probably need to keep them enabled.

6. Uncheck "Register this connection" under IP properties, Advanced settings,
"DNS" tab.

7. Delete the outer NIC IP address, disable Netlogon registration, and manually
create the required records

a. In DNS under the zone name, (your DNS domain name), delete the outer NIC's
IP references for the "LdapIpAddress". If this is a GC, you will need to
delete the GC IP record as well (the "GcIpAddress"). To do that, in the DNS
console, under the zone name, you will see the _msdcs folder. Under that,
you will see the _gc folder. To the right, you will see the IP address referencing
the GC address. That is called the GcIpAddress. Delete the IP addresses referencing
the outer NIC.

i. To stop these two records from registering that information,
use the steps provided in the links below:
Private Network Interfaces on a Domain Controller Are Registered in
DNShttp://support.microsoft.com/?id=295328

ii. The one section of the article that disables these records is done with
this registry entry:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Servic es\Netlogon\Parameters
(Create this Multi-String Value under it):
Registry value: DnsAvoidRegisterRecords
Data type: REG_MULTI_SZ
Values: LdapIpAddress
GcIpAddress

iii. Here is more information on these and other Netlogon Service records:

Restrict the DNS SRV resource records updated by the Netlogon service

[including GC]:

http://www.microsoft.com/technet/tre...o_rr_in_ad.asp

b. Then you will need to manually create these two records in DNS with the
IP addresses that you need for the DC. To create the

LdapIpAddress, create a new host under the domain, but leave the "hostname"
field blank, and provide the internal IP of the DC, which results in a
record that looks like:
(same as parent) A 192.168.5.200 (192.168.5.200 is used for illustrative
purposes)

i. You need to also manually create the GcIpAddress as well, if this is a
GC. That would be under the _msdcs._gc SRV record under the zone. It is created
in the same fashion as the LdapIpAddress mentioned above.

8. In the DNS console, right click the server name, choose properties, then
under the "Interfaces" tab, force it only to listen to the internal NIC's
IP address, and not the IP address of the outer NIC.

9. Since this is also a DNS server, the IPs from all NICs will register,
even if you tell it not to in the NIC properties. See this to show you how
to stop that behavior (this procedure is for Windows 2000, but will also
work for Windows 2003):
275554 - The Host's A Record Is Registered in DNS After You Choose Not to
Register the Connection's Address:
http://support.microsoft.com/?id=275554

10. If you haven't done so, configure a forwarder. You can use 4.2.2.2 if
not sure which DNS to forward to until you've got the DNS address of your
ISP.
How to set a forwarder? Good question. Depending on your operating
system,choose one of the following articles:

300202 - HOW TO: Configure DNS for Internet Access in Windows 2000 http://support.microsoft.com/?id=300202&FR=1

323380 - HOW TO: Configure DNS for Internet Access in Windows Server 2003
(How to configure a forwarder):
http://support.microsoft.com/d/id?=323380

Active Directory communication fails on multihomed domain controllers http://support.microsoft.com/kb/272294

<==*** Some additional reading ***==>
More links to read up and understand what is going on:

292822 - Name Resolution and Connectivity Issues on Windows 2000 Domain
Controller with Routing and Remote Access and DNS Insta {DNS and RRAS and
unwanted IPs registering]:
http://support.microsoft.com/?id=292822

Active Directory communication fails on multihomed domain controllers http://support.microsoft.com/kb/272294

246804 - How to enable or disable DNS updates in Windows 2000 and in Windows
Server 2003
http://support.microsoft.com/?id=246804

295328 - Private Network Interfaces on a Domain Controller Are Registered in
DNS
[also shows DnsAvoidRegisterRecords LdapIpAddress to avoid reg sameasparent
private IP]:
http://support.microsoft.com/?id=295328

306602 - How to Optimize the Location of a DC or GC That Resides Outside of
a Client's
Site [Includes info LdapIpAddress and GcIpAddress information and the SRV
mnemonic values]:
http://support.microsoft.com/?id=306602

825036 - Best practices for DNS client settings in Windows 2000 Server and
in Windows Server 2003 (including how-to configure a forwarder): http://support.microsoft.com/default...b;en-us;825036

291382 - Frequently asked questions about Windows 2000 DNS and Windows
Server 2003 DNS
http://support.microsoft.com/?id=291382

296379 - How to Disable NetBIOS on an Incoming Remote Access Interface
[Registry Entry]:
http://support.microsoft.com/?id=296379

Rid Pool Errors and other mutlhomed DC errors, and how to configure a multihomed
DC, Ace Fekay, 24 Feb 2006 http://www.ureader.com/message/3244572.aspx

don't multihome a dc. This creates nothing but
problems.

[johnvc]

Hello . I have read the responses , but find the solutions rather confusing.
In my case, the second NIC card in my Win2003 DC , DNS, & DHCP server is connected to a switch dedicated for Internal Backup purposes only and with another IP subnet 192.168.x.x.
It has File and Print, MS Client, DNS and Netbios all disabled.
Yet when I Enable the secondary card, after a short while, the secondary DNS IP number is propogated thruout the primary card network and my users begin to experience connection errors.
Is there a simple solution to this?
Thanks for any advice or suggestions, I am at my wits end with this...

I've seen changing the NIC binding order with the protocols help - but
that's not the case for 100% of the issues you see.

Microsoft doesn't recommend having a DC be multihomed (that is have
multiple NICs in the DC connected). I'd plan on changing that in the
near future rather than fixing the symtoms.

As Florian said, multihoming DCs is not recommended. If you *truly* need to
keep the DCs multihomed, I put together a step-by-step to alter a DC
functionality in order to properly register into DNS, however it requires
mutiple changes, including registry alterations.

In my opinion, I would rather have my DCs single homed, and use the
infrastructure's routing to move packets around networks, and not put the DC
on multiple subnets, which also causes problems with AD Site definitions,
because it makes a DC part of more than one Site, which is not recommended
because it goes against the definition of a "site."

Read the following for the step by step. Let us know how you make out.

[gniuz]

This is very interesting info. Ace, where can I find your step-by-step? Thanks

What if a virtual multihomed DC is deployed and configured with a single virtual nic and a second virtual NIC is installed/configured in the last step of the installation/configuration process? Anyone has experience with this?

A multi-homed DC is a multi-homed DC,...physical or virtual is
irrelevant,...it is all the same thing.

272294 - Active Directory Communication Fails on Multihomed Domain
Controllers
http://support.microsoft.com/default...b;en-us;272294

191611 - Symptoms of Multihomed Browsers
http://support.microsoft.com/default...b;EN-US;191611

Multihoming is multihoming, either physical or virtual.

Here some more info, also from Ace Fekay:
-----------------------------------------------------------------------
1. Domain Controllers should not be multi-homed
2. Being a VPN Server and even simply running RRAS makes it multi-homed.
3. DNS,..even just all by itself, is better on a single homed machine.
4. Domain Controllers with the PDF Role are automatically Domain Master
Browser. Master Browsers should not be multi-homed

That first section looks familiar :-)
Looks like I mispelled "PDC" and forgot the "s" on the end of Domain Master
Browsers. I'll blame it on a multi-homed spell checker.

It is just a pure copy and paste from yours, no modifications. :-)

If you correct my spelling I won't tell anyone :-)

It's in the link I posted. Here is it again:

Multihomed DCs with DNS, RRAS, and/or PPPoE adapters

I've slightly updated it in my blog. :-)

Done. :-)

Best regards

[t3rrorbyte]

I accidentally multihomed my DC by plugging the network cable into the wrong NIC, I don't want it to be multihomed and have plugged the network cable into the correct NIC. Can this write up be adapted to remove the binding to the second NIC?

Every time i delete it in the DNS (which is also on the DC) it reappears each time it reloads.

Cheers guys this might just save my bacon

You have to DISABLE the unused NIC in Networking section. Otherwise, it will
still try to register even with the 169.254.x.x address. If disabled,
Windows ignores it.

[t3rrorbyte]

Thank you so much Ace Fekay that has done the trick, DNS back up to full speed.

That is good to hear. You are welcome. If you have any other questions,
don't hesitate to post back.