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! -
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.
