Windows 7 - DNS Resolution Problem - Invalid DNS

Asked By bill caixeiro on 25-Dec-08 11:31 AM
Hi,

My internet provider xplornet assigns 3 DNS servers to my connection.  The
problem is that the first IP address is an invalid IP address
(192.168.175.2) and the Vista system does not try to go to the next DNS
server to resolve any dns requests.  If I change the network settings and
manually type in the other two DNS server IP's, dns resolution works.

Why is Vista not able to check the other DNS servers when the first lookup
fails?

I have an XP laptop that works just fine with the "Obtain DNS server address
automaticall" enabled, so it is a Vista issue.

Thanks.




Michael Walraven replied on 25-Dec-08 12:57 PM
192.168.x.x inplies that a local machine is reporting that it can do DNS.
This is often true for the Router which is correct. (the router is usually
192.168.x.1 but that is not necessarily the way your setup is configured. )


First off would be to determine which machine is 192.168.175.2 and check if
it is hosting a DNS service. One way that happens is if the machine has been
setup to do ICS (internet connection sharing).

As far as your real question as to why it doesn't move on to the next
server, I can't help.

Michael
wra replied on 26-Dec-08 03:51 AM
In article <A606539D-C086-4894-A786-DF8B2F4B55B7@microsoft.com>,

It's not a vista problem.  Probably what's happening is that
there really IS a DNS server running at the address you're using but
it's not properly configured.  So it doesn't know any addresses and
doesn't know where to go to get that information.  DNS has the concept
of a negative answer.  Your DNS client will only go to the next server
in the rotation if the first doesn't answer, but if it sends a negative
answer ("that doesn't exist") it just stops there.

So you need to find out why you're getting that first bad
address.  You can kludge it by manually inserting a correct working
DNS entry in the network configuration.
Richard G. Harper [MVP] replied on 25-Dec-08 04:59 PM
The DNS failover protocol is only invoked if the lookup fails to find a
valid server, not if that server responds but cannot locate the site in
question.  So DNS as configured on your system is doing exactly what it's
supposed to do and there's nothing you can do to change that behaviour.

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