How to alias a UNC Host Name in Windows Server 2003

Locate and then click the following registry subkey:

HKLM\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters
On the Edit menu, point to New, and then click Multi-String Value.
Type OptionalNames, and then press ENTER.
On the Edit menu, click Modify.
In the Value data box, type the NetBIOS names of the old servers (oldserver1, oldserver2 and oldserver3) each on their own line, and then click OK.
This action registers the names in Windows Internet Name Service (WINS)

Locate and click the following key in the registry:
HKLM\System\CurrentControlSet\Services\LanmanServer\Parameters
On the Edit menu, click Add Value, and then add the following registry value:
Value name: DisableStrictNameChecking
Data type: REG_DWORD
Radix: Decimal
Value: 1

Also check these articles from MS
http://support.microsoft.com/kb/829885
http://support.microsoft.com/kb/281308
http://support.microsoft.com/kb/896861