A client computer that logs onto a domain that includes Windows Server 2003 domain controllers AND
Active Directory directory Sites may be authenticated by a remote domain controller instead of by the local domain controller.
The System event log on the local Windows Server 2003 domain controller contains an event similar to:
Event ID: 5807
Source: NETLOGON
User: N/A
Computer: <Computer Name>
Description: During the past number hours there have been number connections
to this Domain Controller from client machines whose IP addresses don't map to any of the
existing sites in the enterprise. Those clients, therefore, have undefined sites and may connect
to any Domain Controller including those that are in far distant locations from the clients.
A client's site is determined by the mapping of its subnet to one of the existing sites.
To move the above clients to one of the sites, please consider creating subnet object(s) covering
the above IP addresses with mapping to one of the existing sites. The names and IP addresses of
the clients in question have been logged on this computer in the following log file
'SystemRoot\debug\netlogon.log' and, potentially, in the
log file 'SystemRoot\debug\netlogon.bak' created if the former
log becomes full. The log(s) may contain additional unrelated debugging information. To filter
out the needed information, please search for lines which contain text 'NO_CLIENT_SITE:'. The
first word after this string is the client name and the second word is the client IP address.
The maximum size of the log(s) is controlled by the following registry DWORD
value'HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Netlogon\Parameters\LogFileMaxSize';
the default is 20000000 bytes. The current maximum size is 20000000 bytes. To set a different
maximum size, create the above registry value and set the desired maximum size in bytes.
The %SystemRoot%\Debug\Netlogon.log file on the local Windows Server 2003 domain controller contains entries like:
MM.DD HH:MM:SS <NetBIOS Domain Name>: NO_CLIENT_SITE: <Client Computer Name> <Client IPaddress>
This behavior will occur if the <Client IPaddress> is NOT defined in the Subnets folder
in Active Directory Sites and Services and it is NOT mapped to an existing site.
To fix this problem:
1. Open Active Directory Sites and Services.
2. Expand Sites.
3. Right-click Subnets and press New Subnet.
4. Type the <Client IPaddress> into the Address box.
5. Type the subnet mask into the Mask box.
6. In the Site Name box, select the site object that contains the local domain controller and press OK.
7. Close Active Directory Sites and Services.