nat wont happen

Unanswered Question
Mar 24th, 2008

We used to use snapgear as our firewall. There were port forwarding configured. When we sit in the office,and browse the web server using external ip address, it will forward the traffic back to internal server.

Now we are using cisco1811. Nat is configured too. From outside, there is no problem. But if we tried to use public address from the inside, the NAT did not happen.

It does make sense to me. But for consistence, how can we use the same ip for inside use as well as outside use.

I hope somebody can understand that.


I have this problem too.
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thotsaphon Mon, 03/24/2008 - 21:08

Hi Lydia,

Just my thought, I would use the internal dns server that can resolve the name of internal server to the internal ip address(private ip address)when I sit in the office.If I go out there I would use the public ip address being natted by cisco 1811 router.

I'm not sure that you are using the name to reference when you want to access the server or use ip address.

Let's say you are using tcp/80 application.I would use http://servername. Now the dns server comes into play.

Hopes this helps


yayasolenet Mon, 03/24/2008 - 21:15

Thank you for the quick reply. This is my first thought. And I added one zone in my internal dns server, it did work. But this one is using dyndns. The zone is I can't create a zone for in my dns server, because I cant add all the hosts into this zone. If it has found the zone and no record, it wont pass to the external dns server.

I just read something talking about NAT with extendable in the end. But it doesnt seem to work with 1811 IOS 12.4(6).



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