2 NICs connection problem

[SilverJOE]

Ok here is the problem,
I have 2 NICs one connected to the public internet and the other to the private one. This is also the domain controller. I leave the computer for few minutes and then come back and i cant connect to the internet unless i disable the NIC the is going to the private network. Is windows getting confused to which one to use. I am not using RRS, i am using NAT through a firewall and i dont think that is the problem. Under DNS i have the Forwarding working to poing to the dns for both the local and the one from ISP. I dont know what the problem is, can anyone help??
Thanks
Joe

 

[BWilson77080]

dont forward to your own dns server, youll just cause it to loop back dns requests internally...it tries the internal dns server first, and then shoots out to any forwarder dns servers...it forwards in the order you have the IPs on the forwarders tab

do you have a static IP (i assume you do)
is the public interface in NAT set correctly with everything (probabaly since you can egt out when the second NIC is disconnected)?
is the private interface in NAT set correctly?

the public interface should be pointing to an external DNS server (on the NIC)

private interface should list itself as the dns server, then your forwarder will take it from there..

sounds like it may be looping itself abck in...take your local dns server out of its own forwarder (unless i misunderstood ya, then let me know and ill re-examine)
and just leave the ISPs DNS server, or list 2 ISP DNS servers if you know 2 of them just for fault tolerance

this will probably fix ya if i understood your problem correctly

BWilson77080
MCSA+MCP, A+

 

[SilverJOE]

Thanks for replying,
I have the forwader set to two dns on the public domain that i got from my ISP, and the private one is not there.I also have the Do not use recursion check box checked. Sometimes i can get online, but after few minutes it just stalls ans tart searching again as if it is looking at the private one for name resolution. I was thinking like you when i was trying to solve the problem but i dont know where is the setting that would take care of the looping back. on the private NIC i have the setting to the DNS server and no default gateway. Is there a setting that you konw of in the dns or dhcp that i am missing and it is causing this?
Thanks

 

[ReddLefty]

There is also a DCHP setting to tell it which NIC card the DHCP will answer to. (DHCP, Properties, Advanced Tab, Bindings) The only thing I can see would be that your DHCP maybe answering to both cards and for some reason you get a request from the WAN for a DHCP address and your DHCP gives it one. By doing so, the server will adjust it's route table to accept traffic from WAN and in the process it will loose communications with your LAN. Of course.. this is all theoritical and would be kinda unlikely since to get a DHCP address, the WAN NIC must answer to a 0.0.0.0 IP request which is not routable... so it can leave your WAN router. But you might as well check it anyhow.. to make sure that everything is ok with your DHCP.



"In space, nobody can hear you click..."

 

[BWilson77080]

i assume youve tried unchecking the do not use recursion checkbox

as long as your using ad integrated zones you should be safe

 

[Seaspray0]

do not use recursion means your dns will attempt to solve the address itself and if it doesn't... too bad. Recursion allows it to go to other DNS servers (i.e. internet servers) to resolve names. The DNS console also has a feature where you can run a test to check resolution.

 

[BWilson77080]

that was my thoughts exactly (what seaspray said)

there is one exception to that of course, if your root hints file has the appropriate DNS servers for your ISP inside it, then your clietns will still be able to connect

other than that...what seaspray said



if youre not using an external empty root DNS server, then you shouldnt disable recursion as recursion means basically "from this DNS box to the next one in line"
with it disabled you essentially saying "im the only DNS server, bow to me"

lol

 

[SilverJOE]

ok thank you guys, i dont know if that is the problem, i will try to use recursion and see if it works, somone told me that i should have it checked because it is a security risk to leave it uncheked. I will post again in few days and tell you if that worked.
Thanks

 

[BWilson77080]

its only a security risk if youre using a primary secondary dns set up...just go into dns and allow zone transfers to only authorized dns servers, that will take care of that

 

[Comptek4]

You could just try removing the gateway from the internal nic card. That way it always gose to the public nic card for internet. This is the way I have my gateway server setup. I was havin the same issue untill I removed the gateway from the internal card