If you are getting "connection refused" errors while trying to reach, from within your local Airport network, no-ip.org type domains that are pointing to a local server on port 80, I have learned of 2 options:
A. set up a DNS server on the local network, behind the firewall.
B. Add the domain thru Netinfo Manager:
1. go into --> Utilities --> NetInfo Manager and authenticate
2. click on "machines" and then click on "localhost"
3. pulldown "Edit" to "Duplicate" and confirm "Duplicate"
4. click on "localhost copy"
5. below in the "Value(s)" column of row "ip_address" highlight "127.0.0.1" and rename to [the local ip mapped to port 80] for instance, "10.0.1.4"
6. in in the "Value(s)" column of row "name" highlight "localhost" and rename to [the domain pointing to your airport] for instance, "jetlag.no-ip.org"
7. now, up top, click back onto "localhost" (your 'localhost copy' should have been renamed to [your domain]), and then confirm the change by clickin "save" in the dialogue box and then "update copy".
8. that's it.
NOTE: choosing option A above will solve the issue for all machines on the local network, choosing option B requires that the steps be taken on EACH macine.
Also, this post is a follow up from a previous post I had where, on 10.1.5, this fix did not work for names that were domains. In 10.2 you may use domains in the name row as described above.