I would piss off the Belkin router just to test the basics.
The less pieces of equipment the easier it is to pin-point the problem. Plug your mac straight into your modem and see if you get internet, make sure your mac is set to connect via DHCP on whatever your connecting with (Ethenet, in...
A friend has the same issue, I couldn't work it out quickly but maybe a Archive and install of the operating system may fix, unless its faulty hardware... very strange, she has a macbook 1.6 ish with 10.5
I'll let you know if she figures it out.
I have no idea what all that blurb means but have a look at the link below I use it and iChat works every time now through my linksys router... You will have to enable UPnP on the routers setup to let the software work. Very simple.
Have a look here...
This will fix it!
I had the same issue with a few routers (linksys, netgear and semens) so i use this software LIGHTHOUSE for osx. With 10.4 iChat never worked through routers without lighthouse however now with 10.5 it sometimes does but if all else fails i fire it up and it workes every...
I've had the same trouble you have had with the WRT54GXv2 and Mac osx. Currently I have the firmware version 2.00.20 on my router and everything works fine on my mac on all browsers. From memory before I updated the firmware I found the browser iCab ver 3 for mac, this would load up the routers...