On a Vista x64 PC with a wired connection to a Server 2003 Domain environment, a DHCP-assigned IP, and an empty hosts file, intermittently any attempt to ping, telnet or otherwise resolve a particular machine name (or FQDN) (and not always the same machine) will begin to fail with an "unable to resolve" error. The trigger that causes a machine name to stop resolving has not been identified.
However, when this situation occurs, nslookup is still able to successfully resolve the name, and access to the machine via IP address (ping, telnet, etc) is also successful.
UPDATE: "ipconfig /displaydns" returns:
myserver.mydomain.local
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Name does not exist.
So it seems a lookup failure has been recorded. The lack of TTL normally present on all other entries returned is also concerning.
The simplest way I've found to recover this situation is to release and renew the DHCP lease; "ipconfig /flushdns" does not work.
How can I resolve this or how can I extract more diagnostic information to find the root cause?
Thank you
Best Answer
This sounds like name resolution is failing. Is the DNS server also set via DHCP? When you do the nslookup do you explicitly give the DNS server IP? There are issues with some name resolution servers because of the IPv6 stack on Vista so you could see if ping -4 works when ping does not (the Vista IP stack attempts name resolution using IPv6 first and then moves to IPv4 but some resolvers reject the subsequent IPv4 request: see http://technet.microsoft.com/en-gb/library/bb878121.aspx for more information on this). I'm not a windows expert so my usual line of attack would be to look at the packets on the LAN, you might prefer to explore the windows side of things.