A problem querying a different DNS server
 

Hi. I have a problem with DNS querying to a Different Server. Our network setup has several linux servers in our DMZ. We have 2 DNS servers setup at our location and what we want to do is point all the servers in the DMZ to our Internet providers DNS servers. I have been able to accomplish this on every server but one. I looked in the firewall and made sure DNS was allowed in and out for this server. So it should work with no problems, but when I comment out our current DNS servers in resolv.conf and add our providers we are no longer able to query DNS. As soon as I put it back to the way it was everything works again.

So my thought was maybe the firewall rule had an error in it that I missed so I copied the line that referenced that server and pasted it right below it and changed the IP to a new machine I just setup. This new machine queries DNS fine with the rule that was copied. That means that there is something wrong with that one server. The thing is what.

So here I am needing your suggestions on where to look next. The person that built this machine is long gone. It is running Red hat 2.2.12-20 and bind 8.2.3-0.6.x . Very old I know. What I am doing is building a new box to replace this one but right now I need to get the DNS working on the old server. Does anyone have any suggestions or has heard of this problem. I have been googling and not finding anything.

Thanks

What happens when you try to ping your ISP's DNS servers from the problem machine? What happens when you do an nslookup against those servers?

Hi. With the current setup it resolves just fine when I do a nslookup from the server AMD.

Server: jacob.madhat.com
Address: 104.156.9.35

Name: ns1.ussignalcom.net
Address: 64.186.63.132

I contacted them to make sure our IP Class was in their allow list for DNS and it is.

When I put in their DNS servers in the resolv.conf the nslookup does not resolve at all.

I think I may have confused people about my problem. Sorry for the confusion. Yes, this is being used as a DNS server. Right now it is being pointed to 2 DNS Proxy servers in our network. This setup works just fine. But when we try to bypass the DNS proxy servers and go straight to US Signals DNS servers it will not return anything when we do a "dig google.com". But if I set it back to the DNS Proxy Servers and do a "dig google.com" It responses. Dig and ping are the testing tools I have been using. All I am trying to do is bypass the DNS proxy servers and go straight to our providers DNS server.

I hope that makes sense. I appreciate your help

Well, we dropped the firewall and it still will not resolve DNS when we put in our providers DNS server in the resolv.conf file. So it is something specific to our DNS machine. But the question is what. Does anyone have an ideas of where I should check next? Thanks