ncomper
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NSLOOKUP works but pinging FQDN does not on WIndows 7 machines
Hi All
I have a few machines with strange DNS issues that are also intermittent
Issue
Accessing an internal system jira.mydomain.com normally works OK however on occasions some users reports it fails, if we then try and ping jira.mydomain.com from the users machine it says unable to resolve, if I do an nslookup it resolves fine. If you leave it a while it just starts working again.
My own machine has never had an issue yet we are on the same VLAN and have same DNS servers configured
Steps I have checked so far
DNS servers they get are correct
DNS search suffixes are configured
Firewall is disabled
No obvious errors on DNS servers ( AD integrated Zones )
iconfig /flushdns does not fix
Anyone got any ideas, I see a lot of people report the same issue but cant seem to find a conclusive post with a fix
I have a few machines with strange DNS issues that are also intermittent
Issue
Accessing an internal system jira.mydomain.com normally works OK however on occasions some users reports it fails, if we then try and ping jira.mydomain.com from the users machine it says unable to resolve, if I do an nslookup it resolves fine. If you leave it a while it just starts working again.
My own machine has never had an issue yet we are on the same VLAN and have same DNS servers configured
Steps I have checked so far
DNS servers they get are correct
DNS search suffixes are configured
Firewall is disabled
No obvious errors on DNS servers ( AD integrated Zones )
iconfig /flushdns does not fix
Anyone got any ideas, I see a lot of people report the same issue but cant seem to find a conclusive post with a fix
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ASKER
Thanks
I have been doing some research and it appears that its a client side issue with the DNS resolver, when doing an nslookup the query is always sent to the DNS server (Which works)
When pinging by fqdn it uses the hosts local cache first and this is where I believe its failing and the request never makes it to the DNS server
I have been doing some research and it appears that its a client side issue with the DNS resolver, when doing an nslookup the query is always sent to the DNS server (Which works)
When pinging by fqdn it uses the hosts local cache first and this is where I believe its failing and the request never makes it to the DNS server
It's true that nslookup uses its own resolver.
Did you do a network capture during a period when the name can't be resolved?
Did you do a network capture during a period when the name can't be resolved?
ASKER
No that's my next step thanks
ASKER
Thanks, after all that it turned out there was a legacy efficient IP box that some users where querying that was missing some A records
Check the health of DCs by dcdiag /q and repadmin /replsum.When the issue occur check the event log on workstation and server too for any errors and warning and post the same.
I you have antivirus installed disable the same temporarly.