Thread: Force prefernce in logon server

Force prefernce in logon server

I have 3 DCs in this single forest domain all on same network. Is there a
method to force the preference of logon server?

Carl

2. Ace Fekay [Microsoft Certified Trainer] Guest

Re: Force prefernce in logon server

In news:eOcjhyvlJHA.4028@TK2MSFTNGP03.phx.gbl,
> I have 3 DCs in this single forest domain all on same network. Is
> there a method to force the preference of logon server?
>
> Carl

Hi Carl,

Yes, it is possible. You would change the weight and/or priority with the
SRV records. That is done on a DC's netlogon registry, and not in DNS. This
is because the netlogon service is what registers that data into their
respective SRV folders.

When changing them, keep in mind a client will attempt to contact a server
with the lowest priority first. If there are more than one server with the
same priority, DNS load balancing is used when selecting the target server.
If the weights are changed with the same priority, then a server is chosen
based a percentage by dividing the weigth by the sum of all weights of all

Let's say you have 3 DCs: DC01, DC02 and DC03. Weights are assigned as
follows:
DC01 = 10
DC02 = 20
DC03 = 30

In this example:
DC01 will be contacted 1 out of every 6 times (10/(30+20+10))
DC02 will be contacted 2 out of every 6 times (10/30(20/(30+20+10)))
DC03 will be contacted 3 out of every 6 times (10/20(30/(30+20+10)))

You can use nslookup to find the SRV weights:
nslookup
q=srv
_ldap._tcp.dc01._msdcs.domain.com

Make sense? Next week, we'll go over the Wall Street Bailout Fund (TARP) and
try to figure that one out!

Anyway, back to the subject. You can read more about it here:
How DNS Support for Active Directory Works
http://technet.microsoft.com/en-us/l.../cc759550.aspx

AD Cookbook by Robie Allen and Laura E. Hunter

JSI Tip 4527. How can I manage which Windows 2000 domain controller a client
contacts? (WIndows 2000 & 2003 are the same):
http://windowsitpro.com/article/arti...-contacts.html

I hope that helps.

--
Ace

This posting is provided "AS-IS" with no warranties or guarantees and
confers no rights.

Ace Fekay, MCSE 2003 & 2000, MCSA 2003 & 2000, MCT
Microsoft Certified Trainer
aceman@mvps.RemoveThisPart.org

For urgent issues, you may want to contact Microsoft PSS directly. Please
check http://support.microsoft.com for regional support phone numbers.

3. Jorge Silva Guest

Re: Force prefernce in logon server

Hi
Additionally you can isolate the DC and the clients in a given dedicated
site with the proper subnet assign and apply the
http://support.microsoft.com/kb/306602.

--

I hope that the information above helps you.
Have a Nice day.

Jorge Silva
MCSE, MVP Directory Services

"Ace Fekay [Microsoft Certified Trainer]" <firstnamelastname@hotmail.com>
wrote in message news:eDqEoYwlJHA.4760@TK2MSFTNGP04.phx.gbl...
> In news:eOcjhyvlJHA.4028@TK2MSFTNGP03.phx.gbl,
> NGReader <carl@anywhere.com>, posted the following:
>> I have 3 DCs in this single forest domain all on same network. Is
>> there a method to force the preference of logon server?
>>
>> Carl

>
> Hi Carl,
>
> Yes, it is possible. You would change the weight and/or priority with the
> SRV records. That is done on a DC's netlogon registry, and not in DNS.
> This is because the netlogon service is what registers that data into
> their respective SRV folders.
>
> When changing them, keep in mind a client will attempt to contact a server
> with the lowest priority first. If there are more than one server with the
> same priority, DNS load balancing is used when selecting the target
> server. If the weights are changed with the same priority, then a server
> is chosen based a percentage by dividing the weigth by the sum of all
> weights of all DCs in an AD Site.
>
> Let's say you have 3 DCs: DC01, DC02 and DC03. Weights are assigned as
> follows:
> DC01 = 10
> DC02 = 20
> DC03 = 30
>
> In this example:
> DC01 will be contacted 1 out of every 6 times (10/(30+20+10))
> DC02 will be contacted 2 out of every 6 times (10/30(20/(30+20+10)))
> DC03 will be contacted 3 out of every 6 times (10/20(30/(30+20+10)))
>
> You can use nslookup to find the SRV weights:
> nslookup
> q=srv
> _ldap._tcp.dc01._msdcs.domain.com
>
> Make sense? Next week, we'll go over the Wall Street Bailout Fund (TARP)
> and try to figure that one out!
>
> Anyway, back to the subject. You can read more about it here:
> How DNS Support for Active Directory Works
> http://technet.microsoft.com/en-us/l.../cc759550.aspx
>
> AD Cookbook by Robie Allen and Laura E. Hunter
>
> JSI Tip 4527. How can I manage which Windows 2000 domain controller a
> client contacts? (WIndows 2000 & 2003 are the same):
> http://windowsitpro.com/article/arti...-contacts.html
>
> I hope that helps.
>
> --
> Ace
>
> This posting is provided "AS-IS" with no warranties or guarantees and
> confers no rights.
>
> Ace Fekay, MCSE 2003 & 2000, MCSA 2003 & 2000, MCT
> Microsoft Certified Trainer
> aceman@mvps.RemoveThisPart.org
>
> For urgent issues, you may want to contact Microsoft PSS directly. Please
> check http://support.microsoft.com for regional support phone numbers.

4. Meinolf Weber [MVP-DS] Guest

Re: Force prefernce in logon server

As said from the others you can configure it:
http://technet.microsoft.com/en-us/l.../cc787370.aspx

http://support.microsoft.com/kb/816587

Best regards

Meinolf Weber
Disclaimer: This posting is provided "AS IS" with no warranties, and confers
no rights.

5. Jorge de Almeida Pinto [MVP - DS] Guest

Re: Force prefernce in logon server

WHY you do want to do that? Explain that first please

--

Cheers,
(HOPEFULLY THIS INFORMATION HELPS YOU!)

# Jorge de Almeida Pinto # MVP Identity & Access - Directory Services #

BLOG (WEB-BASED)--> http://blogs.dirteam.com/blogs/jorge/default.aspx
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* This posting is provided "AS IS" with no warranties and confers no rights!
* Always test ANY suggestion in a test environment before implementing!
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news:eOcjhyvlJHA.4028@TK2MSFTNGP03.phx.gbl...
> I have 3 DCs in this single forest domain all on same network. Is there
> a method to force the preference of logon server?
>
> Carl
>
>
>