Force DNS server to return fix result?

  • Thread starter Thread starter Chai
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Chai

Hi there,

My company network have multi subnets. And my DC have
multiple - 3 NICs.

My DC act as DNS, AD, ISA and SQL server.

My client complain login process slow (up to 5 minutes). I
found that this is due to the DNS problems. When I ping
the Server from client PC, I get different IP address
cause the server got 3 NICs.

For security reason, I only permit the client PCs access
to 1 NIC on the Server.

Can I force the DNS to return only the IP address I want?
I try to delete the other 2 IP address (A record) but
whenever the DNS restart or after a while the record
regsiter itself again!

Any ideas?

Thanks.

Chai
 
Chai said:
Hi there,

My company network have multi subnets. And my DC have
multiple - 3 NICs.

My DC act as DNS, AD, ISA and SQL server.

My client complain login process slow (up to 5 minutes). I
found that this is due to the DNS problems. When I ping
the Server from client PC, I get different IP address
cause the server got 3 NICs.

For security reason, I only permit the client PCs access
to 1 NIC on the Server.

Can I force the DNS to return only the IP address I want?
I try to delete the other 2 IP address (A record) but
whenever the DNS restart or after a while the record
regsiter itself again!

Any ideas?

Thanks.

Chai

Unfortunately, multihomed DCs and DNS servers (especially if they are both)
are VERY problematic. It requires additional administrative tasks and steps
and mutliple registry changes to *force* them to work properly, and/or to
return only one IP. This involves stopping the LdapIpAddress, the
GcIpAddress, and the registered nameserver IPs and then force one IP, for
the above settings, etc, and ensuring the SRVs still register properly.

So you see, it's actually *highly* recommended to use a member server as a
mutlihomed machine/router and choose one of your subnet to house your DC/DNS
server.

--
Ace

Please direct all replies to the newsgroup so all can benefit.
This posting is provided "AS-IS" with no warranties and confers no
rights.

Ace Fekay, MCSE 2000, MCSE+I, MCSA, MCT, MVP
Microsoft Windows MVP - Active Directory
 
Hi Ace,

Thanks for your reply.

Do you have any documents/link to web site to show how
difficult to configure it so that I can show to my
manager! ( I can request another server for it! ^_^)

Thanks

Chai
 
In
Chai said:
Hi Ace,

Thanks for your reply.

Do you have any documents/link to web site to show how
difficult to configure it so that I can show to my
manager! ( I can request another server for it! ^_^)

Thanks

Chai

Actually they're all strewn about in this newsgroup between myself and
others posting responses. Steps include to kill the registration of your NIC
cards thru the registry. You first identify the GUID for each NIC. Then you
would publish (thru reg) what IPs you want in DNS, then you need to adjust
the binding order to insure the NIC you want to respond on. Then another reg
entry to kill the GcIpAddress and the LdapIpAddress. Then you publish once
again thru the reg which IP you want for those two values. But need to
insure that the SRVs get registered properly., Then if RRAS is on it, it
complicates it a bit. Then if this is also a NAT server, then there can be
problems with routing between subnets because of the PDU size. LDAP requires
a PDU or 300kb, but once enabled as a NAT, and you have multiple private
interfaces, AD communication gets thwarted and requires another change. This
can cause client logon trouble as well as GPOs to fail because of mutliple
GC addresses come up, as they do on a multi homed DC/GC, then with round
robin, you never know which one will answer and if it;s one on another
subnet, then the system may not route it properly so therefore it can't get
to it, even though the machine is on the same subnet.

Here's a repost of past posts I sent to explain some of it to others. They
maybe mixed a bit, but you can see the jest of it. ALl the instructions are
here to make it work. But it;s something you have to monitor to make sure it
doesn;t cause any other issues. I've setup a couple machines thru this
method, but it's a pain. If you had a member server doing this, (doesn't
have to be an expensive box, just a cheapo desktop will do the trick), you
would be better off.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In
Steve March said:
Hello,
I am having a problem with our Windows 2003 domain controllers.
The domain is in Windows 2003 native-mode and there are only 2
DC/GC's in the same subnet that everyone authenicates off of from
many different subnets over the WAN. The hosting company requires us
to use 3 NIC's in all of our servers; 1 for production, 1 for backup,
and 1 for management. The first 2 months we ran into a few problems
trying to install the other DC and also Exchange Servers into the
domain. We discovered by disabling all but the production NIC we got
around the problem. After we had everything installed we re-enabled
all NIC's and everything worked fine for 2 months until we rebooted
the DC's. After applying 4 security patches and rebooting over the
weekend, everything worked fine until users started to log in Monday
morning. Most users experienced very slow logins and other
authentication processes such as intranet based apps failed. Logging
into the DC's were very slow (minutes). Authentication generally
failed but every now and then things started to clear up to only fail
later on.

AD Users and Computers failed to work and DNS MMC would not start up
at all. AD U&C error message: "Naming information cannot be located
because : This operation returned because the timeout has expired".

In the Application event log on the domain controller during the time
I logged in:
Source :UserEnv Event ID: 1006 Description: Windows cannot bind to
domain. (Timeout). Group policy processing aborted.

We backed out the patches but that didn't help. We discovered that
if we disable the non-production NIC's, everything is instantly
fixed. The hanging DNS MMC pops right up, logins return to normal
speed, and AD Users & Computers works fine on the DC's and on remote
PC's.

Initially we thought it was a DNS problem. We worked with Microsoft
and applied KB 272294 and 2 registry changes discussed in KB 292822
so that only the production NIC IP addresses would show up in DNS.
After some testing logging in and authenticating, everything worked
fine until the next morning when users logged in again the problems
came right back. We disabled the non-production NIC's again and the
problem was fixed instantly again. So now we are working fine except
our hosting center and manage or backup the DC's with the other NIC's
disabled. We think it may be some routing issue with the DC's but we
are not sure.

Any ideas?

Please respond to the group and not to my address (that is wrong)
because I don't want to receive SPAM.

Thank you,
Steve March, MCSE NT4/2000

Not saying it doesn't work, but those articles are based on W2k. The
registries are similar, but I know some of the registration entries on W2k
have been changed on W2k3. Part of the issue you're seeing is with mutli
NICs, when opening ADUC or any other domain requests, it maybe getting the
wrong IP that is registered for the SRV resource. BTW- we always suggest to
NEVER mutlihome a DC and especially never to put RRAS on it either. Suggest
a member server for that. But in many cases, I can understand that may not
be possible in your environement.

Suggestions, and keep in mind, when mentioning "other NICs", they are the
subnets that the NICs are on that your AD infrastructure is not on.

1. Insure that all the NICS only point to your internal DNS server(s) only
and none others.

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 NetBIOS on the other NICs (i know you did that thru the reg with
that article, but insure that it's disabled in NIC properties too). May want
to take a look at this to stop NetBIOS on teh RRAS interfaces:
296379 - How to Disable NetBIOS on an Incoming Remote Access Interface [Reg
Entry]:
http://support.microsoft.com/?id=296379
Otherwise, RRAS or not, it will cause duplicate name errors because Windows
sees itself with multi names thru the Browser service but with different
IPs.

4. Disable File and Print services and disable MS Client on the other NICs.
Uncheck reg this connection in DNS tab of IP properties/Advanced. Now if you
need these for whatever reason for resource access from clients, then you
would probably have to keep them on.

5. In DNS, delete the other NIC references for the LdapIpAddress - the blank
domain FQDN - that looks like (same as parent). To stop it from registering
that info, use this method (taken from
http://support.microsoft.com/?id=295328):
==========================
To disable only the registration of the local IP addresses, set the
following registry value:
Key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Netlogon\Parameters

Registry value: DnsAvoidRegisterRecords
Data type: REG_MULTI_SZ
Values: LdapIpAddress
GcIpAddress
After you set this value, you must manually register your publicly available
IP addresses for your domain to appear as:
Same as parent folder Host "publicIP" DO that by just rt-clicking, new host,
leave the hostname blank, and enter the IP of the internal NIC
==========================

6. In DNS, _msdcs.gc, delete the IP addresses referencing the other NICs. I
would follow this article to stop the GC records from the other NICs
registering sine this is a major cause of concern for logons. You would need
to manually create the GC entry of the internal NIC.
Restrict the DNS SRV resource records updated by the Net Logon service
[including GC]:
http://www.microsoft.com/technet/tr...proddocs/standard/sag_dns_pro_no_rr_in_ad.asp

7. Since this is 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 (for W2K, but may work):
275554 - The Host's A Record Is Registered in DNS After You Choose Not to
Register the Connection's Address:
http://support.microsoft.com/default.aspx?scid=KB;en-us;275554&
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~



And then this one:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
================================
This will work to avoid that "Blank Domain FQDN" (as I call it) Private IP
that you don't want to register. Step 2 is to actually publish the actual IP
that you want in there to come up all the time.

1.You need to disable the local IP address registration without stopping
netlogon from registering SRVs. Otherwise, you'll create a blank domain FQDN
with the external IP and delete the internal private IP just to find that
netlogon will re-register promptly every 60 minutes.
This will take care of that:
(taken from http://support.microsoft.com/?id=295328)
To disable only the registration of the local IP addresses, set the
following registry value:
Key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Netlogon\Parameters

Registry value: DnsAvoidRegisterRecords
Data type: REG_MULTI_SZ
Values: LdapIpAddress
GcIpAddress


2. You'll want to automatically register the external IP without having to
mess with it or netlogon delete it on you.

In circumstances in which the list of IP addresses the DNS server listens to
and serves is different from the list of IP addresses published (registered
by the DNS Server service), use the following registry key:

(From http://support.microsoft.com/?id=246804)

PublishAddresses
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DNS\Parameters

Data type: REG_SZ
Range: IP address [IP address]
Default value: blank

This specifies the IP addresses you want to publish for the computer.

Put those two keys and their values in and you're set.
================================
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~




~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Also, how to kill registration (per NIC) prior to setting the above
publishing records:
246804 - How to Enable-Disable Windows 2000 Dynamic DNS Registrations (per
NIC too):
http://support.microsoft.com/?id=246804
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

275554 - The Host's A Record Is Registered in DNS After You Choose Not to
Register the Connection's Address [It still registers]:
http://support.microsoft.com/default.aspx?scid=KB;en-us;275554&
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
--
Regards,
Ace

Please direct all replies to the newsgroup so all can benefit.
This posting is provided "AS-IS" with no warranties and confers no
rights.

Ace Fekay, MCSE 2000, MCSE+I, MCSA, MCT, MVP
Microsoft Windows MVP - Active Directory
 
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