Would sharing cable through router affect online gaming?

[Mucho]

I want to get a Lynksys router to share a cable connection between two computers, would this affect playing CS online? Do you have to disable the firewall?

 

[Xenon14]

No, unless both computers are using high bandwidth simultaneously. You will, however, have problem hosting. I have yet to figure out how to do so.

 

[KevinMU1]

In the linksys router, you can specify DMZ hosting which essentially just routes all the traffic directly to your computer's internal network IP, that basically is a complete bypass of the router and any firewalling.