Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

We have a Cisco 5510 Router and I can succesfully configure port forwarding from the external interface to a port on an internal address. If I access this from the outside it works correctly, but if I access this from the inside it does not work. How do I make the internal requests resolve correctly?

share|improve this question
up vote 1 down vote accepted

Presuming you are not trying to access the outside from the inside and loop back around which would be silly because it circumvents the basic usage of the ASA or any firewall device just manually add the entries in your dns server.

share|improve this answer

I am not sure how to enable it as I have not used this model, however this is due to NAT Loopback and is usual behaviour when it is disabled. Look in the manual or settings and see anywhere if you have the option to enable it.

I am trying to find the option for you now... if I find how to do it, I will edit this answer.

Edit - still not found it, but someone on the Cisco forums asked a similar question and the response was to use a feature called "DNS doctoring"

share|improve this answer

Standard for Cisco equipment. When I had Cisco and was hosting my own domains as well, I just setup BIND for split-zone DNS. Queries from the outside would resolve to the outside interface and queries from the inside then resolve to the inside interface. Thus, going direct instead of trying to bounce off the firewall.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.