what is the output of ' ifconfig '
Do you see a wan ip in there
how are you connected to the internet example:

My Setup :
Internet - aDSL Modem - Router
Wan(96.*.*.*) - 192.168.1.1 - 192.168.2.1

When you provider is a adsl provider there is probably already a router in you modem and you need to set the asus to listen to 192.168.2.1
you can configure this setting in the /etc/config/network - now it is 192.168.1.1