Hmm.
On some of the older models, the default port for remotely accessing was set to 80. You can change this to something else. Go to Admin Config-->Access-->InternetSide Remote Addressing.
And here, I just copied the text from the help panel on the side concerning this function, hope this helps:
Internet Side Remote Access Setting
IP Address and Port Number to allow remote access from the Internet.
Permit configuration from the wired Internet
Permits administration from a wired computer on the Internet side. If this is selected, enter an IP address and a port number from which remote access from the Internet side is permitted.
Access from the Internet side is not logged.
Permission IP address
Enter the IP address that will be allowed to remotely manage the router from the Internet side.
To allow all IP addresses, leave this box blank.
Permission Port
Enter the port number for remotely accessing the AirStation’s configuration GUI from the Internet side. Ports between 1 and 65535 may be set.
To remotely configure the AirStation from the Internet side:
Type the following into a browser window (assuming port 8080 and a Internet side IP address of "1.2.3.4"): "http://Http://1.2.3.4:8080".
NAT must be enabled for this to work.