Hello, I have two DNS servers (192.168.0.128 and .129) on the network. All my workstations (XP and Vista) are configured to use192.168.0.128 as the preferred DNS and .129 as the alternate. When .128 fails, the XP machines will automatically query the alternate DNS without any issue. However the Vista machines are still stuck with .128 so DNS resolution failed. I search for clues for quite a while now but could find anything. Hope someone has come across thisand give me some pointers. Thanks in advance. Kam

Hi, Please collect the following information on the Windows Vista machine for further research: 1. Windows IP Configuration by using the command ipconfig /all. 2. Network Monitor:================1) Download NetMon3.1 from the following website and install it on the Windows Vista machine:http://www.microsoft.com/downloads/details.aspx?FamilyID=18b1d59d-f4d8-4213-8d17-2f6dde7d7aac&DisplayLang=en2) Log onto the machines, right-click the Netmon icon and select Run as Administrator to launch NetMon3.1.3) In the Microsoft Network Monitor 3.1 window, click Create a new capture tab 4) In the new tab, select all the Network Adapters in the Select Networks window.5) After that, press F10 to start NetMon.6) Reproduce the issue. Once the issue occurs, go back to the NetMon window and press F11 to stop the NetMon.7) Press Ctrl+S to save the Netmon file. After that, please zip and upload the above two files to the following space:https://sftasia.one.microsoft.com/choosetransfer.aspx?key=fb71327f-f8ea-40c2-a26e-d421455aa916 Password: r#fMKh0ggeRDSIn addition, please understand that alternate DNS server will only be used if the preferred DNS server does not respond. That is, if the machine receives response from the DNS server, it will not try to contact the alternate DNS server even if the response contains incorrect record.

Thanks Joson. I uploaded the data files as you recommended. In fact I see the Vista client did query the alternate DNS server but nslookup showed timeout (Please see output file). All objective network conditions are the same, why XP clients don't have such issue but just happened to Vista. Any help would be appreciated. Kam

Hi Kam, Yes, Windows Vista machine will not try to contact the alternate DNS server when you attempt to resolve the computer name by using the command nslookup. It is by design like Windows Server 2003. However, please understand it does not indicate that Windows Vista machine will not query the alternate DNS server when there is no response from the primary DNS server. You can verify it using the command ping. For example, you can let the primary DNS server offline, then type the command: ping computername on the Windows Vista machine. You should see that the Windows Vista machine contacts the alternate DNS server to resolve the computername. Hope the information is helpful.

Thanks for the info Joson. I tried PING and it worked as you said. Does Internet Explorer behave similarly to nslookup as far as DNS is concerned? It failed to open a webpage when I disable the primary DNS server.

No, as far as I know, only the nslookup command doesnt attempt to contact the alternate DNS server. I would like to know if you are browsing an internal or Internet website. If it is an Internet website, please confirm if you has added a correct Forwarder on the alternate DNS server.

Can you expand on this? You say it is by design that a Vista or Windows 2003 server machine will not contact the alternate DNS server. Why? Isn't that the concept of having the alternate - to respond if the primary isn't available?Then what does a Vista or Windows 2003 client do if the primary DNS server isn't available, give up? If so, this would seem to be a step backward.Thanks.

I have a simple AD setup at home with AD + DNS running on a 2003R2 SP2 server. When I disconnect the AD/DNS server from the network my updated Vista client PC will not use the Alternate Public DNS server I have configured for it. This seems not normal, what is the purpose of having any alternate DNS's if they do not automatically start resolving after a primary failed attempt????