When a client computer connects to a Windows 2000 server using an alias, the client receives:

System error 52 has occurred.
A duplicate name exists on the network.

This error occurs when you attempt to connect to the server by using a CNAME alias that is created in the DNS zone:

net view \\alias.<domain name.com>

where alias is a CNAME record that is created for the server in the <domain name.com> zone. Because the server is not listening on the alias, it does not accept connections to that name.

To fix the problem, you must be running SP4 (Service Pack 4) on the server for which the CNAME record was created:

1. Copy / Paste the following to a DisableStrictNameChecking.reg file:

REGEDIT4

\[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\parameters\]
"DisableStrictNameChecking"=dword:00000001

2. Merge the DisableStrictNameChecking.reg file with the server's registry, or run regedit /s DisableStrictNameChecking.reg.

3. Stop the Server service.

4. Start the Server service.

NOTE: See Duplicate name error when you connect to a Windows 2000 server using an alias?