Dual Boot question - only Linux to access internet?

I’m sorry if this isn’t the right place to ask this question, but I’m hoping someone here can help.

I’ve got two computers and I want to set up both to dual boot Windoze and Ubuntu 5.10. I just ordered ADSL service from my local phone company (I’ve been on a dial up until now) and they are sending me a Westell router / ADSL modem to install. One of the big reasons I continue to use Linux (even though most of the apps I use are Windoze) is for it’s great security and virus protection while using the internet.

What I want to set up is this (highest priority):

a. Both computers can access the internet, but -only- if they are running Ubuntu. I’m told the Westell router/ADSL modem supports up to 4 network connections, so hardware wise I should be able to do this.

b. File sharing under Windoze through the router, but -no- internet access under Windoze. I don’t know Windoze all that well, does anyone know if I can do this?

I’d also like to be able to (lower priority):

c. File share while both systems are running Ubuntu (I don’t know how to set this up yet).

d. File share while one system runs Windoze and the other Ubuntu (I’ve started to look at “Samba”, but haven’t tried it yet).

Any help or advice you can offer is greatly appreciated. Thanks!!

a) To prevent any access to the internet on the Win machines:
Open Internet Explorer > Tools > Internet Options > Connections > Lan Settings. Now check the proxy server tick box and then just put in the address box something like : bigkahuna.com port : 5555

Click Ok etc

This creates a false proxy that your PC searches for and cant find to get onto the internet. Hence no internet access.

b) It is hard to do no internet access at all, and still allow file sharing.
You could try doing the same as above but then:
1 - click " Advanced " and either use a different protocol ( like FTP) or
2 - put an IP address in the exceptions box that you are allowed to access. ( the other computer ) This is yoiur best option.

c & d ) not sure, but I plan on doing the same thing in about a month with both win and ubuntu. So let me know how you get on.