How to play Counter Strike 1.6 online for free

Counter strike is the #1 online action game in the world, and CS 1.6 its most popular version, I was mad at counter strike few years back , but for now it has been more than one year since I haven't played it for last 1 year as I have no time for it.Counter strike 1.6 can be played online for free, the only requirement is that you should have a fast Internet connection or else you will not enjoy