From what I heard, It seem like what brendan said. They have a big proxy server and look at all the request header, and try to determined if it's the phone or not. Does anyone have experience accessing internet other than web browsing? like FTP, telnet, ssh, VPN? I think we all know that web browsing alone isn't the internet, but I have a feeling that the carrier don't know that. From my point of view, I have problem with the fact they determined what application they allow to use online rather rather than if I tether or not. What if I have some weird software or apps that I wrote myself on my s60. Maybe I should look if there is a proxy server app for my s60.