problems with DHCP in OS X


i have set up Internet Connection Sharing on my roomie's laptop and i can see when i open system preferences that my computer is receiving a connection because the IP number is assigned when in DHCP mode. the problem is that i cannot view web pages and i cannot check my mail. the network admin program included is X shows that packets are being received and that the IP address is present. can any one tell my why i cannot view web pages or check mail? also, i have entered my ISP's DNS #s..this does not help.
please help!
I don't believe any ISP uses DHCP but I could be wrong. Now, I would leave all fields blank as they are optional because a DHCP server provides them all and that is why they use them is for ease. I use DHCP in school with their network. It works fine for me. I simply:

1) I went to System Preferences-->Network

2) Show: Built-In Ethernet

3) Configure: DHCP

4) Left all else blank and as is and it worked right when I connected.

I just thought about something. If you use Automatic Location just start up with the network connected (Ehternet cable) and it will configure and connect automatically to your network settings (which you set as DHCP) or just plug in the Ethernet and than go to System Preferences-->Network-->Show Built-In Ethernet and than try viewing pages and using email.

I am guessing it is using Built-In Ethernet as a port and DHCP. Have you checked other settings in the Network section of System Preferences? A little more info would be helpful. And if someone could give me some information I am missing we would be greatful :) And another thing is you should not be using the Internet Connect application. That is used for PPP and other dial-up connections. Post back with some more info and what you found out.