DNS and NAT Question.

bretjaquish · ‎06-16-2009

Greetings all,

The company that I work for has purchased another company and we both share common subnets. We are thinking of using NAT in the meantime (instead of re-addressing) during the transition.

We plan on using IOS Nat with a router, probably at the remote facility. I am thinking of implementing the "match-host" functionality of IOS so that the addresses look similiar:

10.1.1.4 = 10.121.120.4 (Then the host part is the same)

The question I have relates to DNS. Is there an easier way to implement DNS than new entries on both sides?

If I set the company B servers to forward, they would see entries for their own devices in company A's servers. Wouldn't they?

OR

Would it run through its local database first and if there is a match....then at last resort it would forward the request?

So could we simply point our DNS servers at each other (would this screw up internet traffic)?

Any help would be much appreciated...

Farrukh Haroon · ‎06-17-2009

Cisco IOS does limited DNS rewrite:

http://www.cisco.com/en/US/tech/tk648/tk361/technologies_q_and_a_item09186a00800e523b.shtml#qa31

On PIX/ASA you could do DNS Doctoring:

http://www.cisco.com/en/US/products/ps6120/products_configuration_example09186a00807968d1.shtml

Regards

Farrukh

bretjaquish · ‎06-17-2009

I saw the DNS rewrite article previously. IOS will do A and PRT record rewrites, but I think that is limted to working with static nat (saw on another forum).

Pix/asa is not an option.

bretjaquish · ‎06-17-2009

Ideally we want to perform NAT dynamically with the "match host" parameter. I guess I will need to test this with some DNS servers.