Newbie Firewall Question

[Regs]

Since backdoor-trojans been infesting my computer I had to install a firewall.

Now I'm running a Internet connection share using a crossover cable to one other computer. No router involved. Last time I enabled a firewall on my PC my own DHCP and DNS server got blocked from my ISP. I think this time I will use Kerio that I heard auto-trusts DHCP and DNS ISP info.

I need to:

One: Allow it to use my ISP's Dynamic IP naming server and DNS server
Two: Allow the other PC to use the Internet.

 

[Tiger]

Buy a router and run something like ZoneAlarm for a firewall on each box.