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PIX 501 and WIN2k DNS servers.

Hi form

Can you have both DNS servers (primary and secondary) on the inside interface of the PIX firewall with a private IP scheme (192.168.x.x) ?

I have trying to do this but the DNS server are timing out when resolving name to IP address resolution – not going beyond the PIX.

I have setup conduits for UDP & TCP domain but it is not working

I configured static NATs for the two DNS servers.



Community Member

Re: PIX 501 and WIN2k DNS servers.

There is no reason that this can't work .. I am not sure exactly what your issue is tho ....?

Do you have Primary and Secondary DNS servers that are authoritive servers for you domain on the inside network and you are trying to query a FQDN for you domain from the internet (ie The only thing that you would need is to have a static and access-list (conduit).


Jason Brown

CCIE #10833

VIP Purple

Re: PIX 501 and WIN2k DNS servers.

If I had to take a guess, I would check to make sure you don't have a root (aka ".") domain defined. If you did, then the DNS servers would consider themselves to be the entire Internet, and not bother trying to query the real root servers.

If you do have a root domain defined, delete it. Then configure forwarders to point to your ISPs name servers.

hint: If you are unable to configure forwarders, then you definately have a root domain defined.

Community Member

Re: PIX 501 and WIN2k DNS servers.

Hi all

I have found the answer in the PIX FAQs. Thanks for you help.


If you have your own DNS server inside your network, this obviously won't work because the DNS lookup never transverses the PIX, so there's nothing to fix. In this case, configure you local DNS accordingly or use local 'hosts' files on your PC's to resolve this name. The other option is actually better because it is more reliable. Take the 99.99.99.x subnet off the PIX and router. Choose an RFC1918 numbering scheme not being used internally (or on any perimeter PIX interface). Then put a route statement back to the PIX for this network and remember to change your PIX default route outside to the new IP address on the router. The outside router will receive this packet and route it back to the PIX based on its routing table. The router will no longer ignore this packet, because it has no interfaces configured on that network.

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