PhilBon

Does anyone know how to monitor all packets going in and out of a computer using Visual Basic.Net. I basically want to create a firewall/Program to disallow certain packets, for example if the client wants to go to images.google.com it will detect the DNS info in the packet and drop it or forwarding it to another page. Basically a Proxy on the computer itself. I know this can be bypassed but there are ways to prevent it from being disabled. I know there are programs out there that do this as well as whole network proxies, I just have a current Server Admin tools program that runs on client computers and would like to add this feature.
If you have any ideas of how to accomplish this, it'd be great, Thanks