The problem is starting with Windows Vista, Microsoft changed how DNS lookups are handled. Specifically DNS devolutions and unqualified names. There are two (2) changes. 1. This issue may caused by the different DNS resolve behavior between XP and Vista/7, below are the details: Windows XP: By default, when a machine attempts to resolve unqualified multi-label names, the DNS client will attempt to resolve the name as specified, then append the domains that are listed in the DNS suffix search order. Windows Vista/7: By default, when a machine attempts to resolve unqualified multi-label name, the DNS client will attempt to resolve the name as specified. The DNS suffix search order will NOT be used. Domain Name Devolution http://www.microsoft.com/technet/prodtechnol/windows2000serv/reskit/regentry/93802.mspx?mfr=true You can change this sith GPEdit or add the registry key. There is a second DNS change on resolution but this usually covers 90%+ of the issues. Run the gpedit.msc on Windows Vista/7, then expand to Computer Configuration\Administrative Templates\Network\DNS Client. Under there, enable the option "Allow DNS Suffix Appending to Unqualified Multi-Label Name Queries." Restart the computer and try again. HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters UseDomainNameDevolution = dword 0x1 2. What is an unqualified multi-label name: The name specified in the query contains a dot(s), but is not dot-terminated. To resolve it, try to run the gpedit.msc on Windows Vista client, then expand to Computer Configuration\Administrative Templates\Network\DNS Client. Enable the option “Allow DNS Suffix Appending to Unqualified Multi-Label Name Queries” under there. or HKLM\Software\Policies\Microsoft\Windows NT\DNSClient AppendToMultiLabelName = dword 1 Edit: Found my notes and added references and reg keys.