How does Windows XP choose the most optimal domain controller?

[Guest John Hossbach]

I have been reading http://support.microsoft.com/default.aspx/kb/314861.

 

There is a sentence that says "If the client is communicating with a

domain controller that is not in the closest (most optimal) site, the

domain controller returns the name of the client's site."

 

I am looking for a technical explanation of that process.

--

John

[Guest Colin Barnhorst]

Re: How does Windows XP choose the most optimal domain controller?

 

Have you asked in a networking newsgroup?

 

"John Hossbach" <HossyBldr@nospam.nospam> wrote in message

news:uzP5AfVeIHA.5548@TK2MSFTNGP03.phx.gbl...

>I have been reading http://support.microsoft.com/default.aspx/kb/314861.

>

> There is a sentence that says "If the client is communicating with a

> domain controller that is not in the closest (most optimal) site, the

> domain controller returns the name of the client's site."

>

> I am looking for a technical explanation of that process.

> --

> John

>

[Guest George Yin]

RE: How does Windows XP choose the most optimal domain controller?

 

Hello,

 

Here is an article giving the detailed explanation of this. Please read the

following article in detail, and I am sure you will find the answers.

 

Finding a Domain Controller in the Closest Site:

http://www.microsoft.com/technet/prodtechnol/windows2000serv/reskit/distrib/

dsbc_nar_jevl.mspx?mfr=true

 

Here is a sample just for your reference:

 

A client computer stores its own site information in the registry, but the

computer is not necessarily located physically in the site associated with

its IP address. For example, a portable computer that was moved to a new

location contacts a domain controller in its home site, which is not the

site to which the computer is currently connected. In this situation, the

domain controller looks up the client site on the basis of the client IP

address by comparing the address to the sites that are identified in Active

Directory, and returns the name of the site that is closest to the client.

The client then updates the information in the registry.

 

The following is quoted from the above Technet link which describes the IP

addresses to site name mapping clearly:

 

"When a client that is searching for a domain controller receives the list

of domain controller IP addresses from DNS, the client begins querying the

domain controllers in turn to find out which domain controller is available

and appropriate. Active Directory intercepts the query, which contains the

IP address of the client, and passes it to Net Logon on the domain

controller. Net Logon looks up the client IP address in its subnet-to-site

mapping table by finding the subnet object that most closely matches the

client IP address and then returns the following information:

 

1. The name of the site in which the client is located, or the site that

most closely matches the client IP address.

 

2. The name of the site in which the current domain controller is located.

 

3. A bit that indicates whether the found domain controller is located (bit

is set) or not located (bit is not set) in the site closest to the client.

 

The domain controller returns the information to the client. The response

also contains various other pieces of information that describe the domain

controller. The client inspects the information to determine whether to try

to find a better domain controller. The decision is made as follows:

 

1. If the returned domain controller is in the closest site (the returned

bit is set), the client uses this domain controller.

 

2. If the client has already tried to find a domain controller in the site

in which the domain controller claims the client is located, the client

uses this domain controller.

 

3. If the domain controller is not in the closest site, the client updates

its site information and sends a new DNS query to find a new domain

controller in the site. If the second query is successful, the new domain

controller is used. If the second query fails, the original domain

controller is used."

 

I hope this helps.

 

Sincerely,

George Yin

Microsoft Online Support

Microsoft Global Technical Support Center

 

Get Secure! - http://www.microsoft.com/security

=====================================================

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[Guest George Yin]

RE: How does Windows XP choose the most optimal domain controller?

 

Hello,

 

I am just writing to see how everything is going. If you have any updates

or need any further assistance on this issue, please feel free to let me

know. I am glad to be of assistance.

 

Sincerely,

George Yin

Microsoft Online Support

Microsoft Global Technical Support Center

 

Get Secure! - http://www.microsoft.com/security

=====================================================

When responding to posts, please "Reply to Group" via your newsreader so

that others may learn and benefit from your issue.

=====================================================

This posting is provided "AS IS" with no warranties, and confers no rights.

[Guest John Hossbach]

RE: How does Windows XP choose the most optimal domain controller?

 

This is exactly what I was looking for. Thank you!

--

John

 

 

"George Yin(MSFT)" wrote:

> Hello,

>

> Here is an article giving the detailed explanation of this. Please read the

> following article in detail, and I am sure you will find the answers.

>

> Finding a Domain Controller in the Closest Site:

> http://www.microsoft.com/technet/prodtechnol/windows2000serv/reskit/distrib/

> dsbc_nar_jevl.mspx?mfr=true

>

> Here is a sample just for your reference:

>

> A client computer stores its own site information in the registry, but the

> computer is not necessarily located physically in the site associated with

> its IP address. For example, a portable computer that was moved to a new

> location contacts a domain controller in its home site, which is not the

> site to which the computer is currently connected. In this situation, the

> domain controller looks up the client site on the basis of the client IP

> address by comparing the address to the sites that are identified in Active

> Directory, and returns the name of the site that is closest to the client.

> The client then updates the information in the registry.

>

> The following is quoted from the above Technet link which describes the IP

> addresses to site name mapping clearly:

>

> "When a client that is searching for a domain controller receives the list

> of domain controller IP addresses from DNS, the client begins querying the

> domain controllers in turn to find out which domain controller is available

> and appropriate. Active Directory intercepts the query, which contains the

> IP address of the client, and passes it to Net Logon on the domain

> controller. Net Logon looks up the client IP address in its subnet-to-site

> mapping table by finding the subnet object that most closely matches the

> client IP address and then returns the following information:

>

> 1. The name of the site in which the client is located, or the site that

> most closely matches the client IP address.

>

> 2. The name of the site in which the current domain controller is located.

>

> 3. A bit that indicates whether the found domain controller is located (bit

> is set) or not located (bit is not set) in the site closest to the client.

>

> The domain controller returns the information to the client. The response

> also contains various other pieces of information that describe the domain

> controller. The client inspects the information to determine whether to try

> to find a better domain controller. The decision is made as follows:

>

> 1. If the returned domain controller is in the closest site (the returned

> bit is set), the client uses this domain controller.

>

> 2. If the client has already tried to find a domain controller in the site

> in which the domain controller claims the client is located, the client

> uses this domain controller.

>

> 3. If the domain controller is not in the closest site, the client updates

> its site information and sends a new DNS query to find a new domain

> controller in the site. If the second query is successful, the new domain

> controller is used. If the second query fails, the original domain

> controller is used."

>

> I hope this helps.

>

> Sincerely,

> George Yin

> Microsoft Online Support

> Microsoft Global Technical Support Center

>

> Get Secure! - http://www.microsoft.com/security

> =====================================================

> When responding to posts, please "Reply to Group" via your newsreader so

> that others may learn and benefit from your issue.

> =====================================================

> This posting is provided "AS IS" with no warranties, and confers no rights.

>

>

[Guest George Yin]

RE: How does Windows XP choose the most optimal domain controller?

 

Hello,

 

Thank you for the reply. It is great to hear that it works!

 

If you need any further assistance, please feel free to let me know.

 

Have a nice day!

 

Sincerely,

George Yin

Microsoft Online Support

Microsoft Global Technical Support Center

 

Get Secure! - http://www.microsoft.com/security

=====================================================

When responding to posts, please "Reply to Group" via your newsreader so

that others may learn and benefit from your issue.

=====================================================

This posting is provided "AS IS" with no warranties, and confers no rights.

[Guest PD43]

Re: How does Windows XP choose the most optimal domain controller?

 

v-chanyin@online.microsoft.com (George Yin(MSFT)) wrote:

>If you need any further assistance, please feel free to let me know.

 

It works better if you quote part of the message you are replying to.