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Cisco 800 Router NAT Loopback

G'day Experts,

I have a private network: 192.168.1/24

I have a single public static IP address from my ADSL ISP.

I have a server which hosts a DNS with a private address 192.168.1.10 in my private network.

I have created a NAT 1:1 to my private server 192.168.1.10 to my public IP.

The requests from the internet work fine, my DNS resolve to my public IP address fine.

BUT

Requests from my private network 192.168.1/24 point to my public IP address which my router does not loop back through to my server.

I know a lot of routers/gateways support this feature, I just can't get it to work on my 800 series

Any assistance apreciated.

Cheers,

Arthur.

2 REPLIES

Re: Cisco 800 Router NAT Loopback

Arthur,

It won't work in this case when private network tries to connect the IP of the DNS that is your public IP address on your router. The router won't do a static nat back to the 192.168.1.10. Because the requesting packets are not coming from the outside interface(Internet interface). In case of ASA firewall, it has a dns doctoring to solve this problem. I have never seen any feature on the cisco IOS to do this. What about setting the dns with the private IP address for internal users? (grin)

HTH,

Toshi

New Member

Re: Cisco 800 Router NAT Loopback

G'day Toshi,

I have this config file from a Cisco 800 series which was doing it, I just can' tell how. I have a couple of these Routers at clients places setup by their ISP's that do it.

I refuse to think you can't do it with IOS, so many home brand router/gateways support this feature.

Any assistance very much appreciated.

Cheers,

Arthur

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