I tried a little setup, I have 2 PCs, one is x4 and the other in Atom, the x4 and atom are connected via crossover cable. I use broadband and that is connected via a USB RJ45 adapter. I tried to share internet between these PCs, I did all the process correct at the first attempt itself, well the process is simple, both the PC are connected with private IP of 192.168.137.x series and then the internet lan adapter (lets call it Local Area Network 2 or Lan 2 for ease) is set to share with lan 1 like this:
In the above pic ‘home’ is the name of my lan 1 (private network). Then why did it take 8hrs for such simple one. The answer is not simple, I use Zone Alarm Firewall, but still it is not the problem because I added the private network 192168.137.x to Trusted Zone, which means any activity on that network is almost ignored or say PERMITTED.
The issue was that I was using Zone Alarm Free Version and to my shock I found that free version does not support the ICS (Internet Connection Sharing) .
So I thought why not to take a trail version of Zone Alarm Pro for 30 days so that mean while I can search for an alternative. Again another punch , zone alarm products are upgraded constantly like any other good product life cycle, the issue now is the new Pro version is 10 and it does not support ICS.
After thorough research and testing, found out that ICS can work is the Internet Zone is set to Medium Security, by default it is High, but by setting it to medium we can get the ICS working. Also, by browsing the net came to know that medium security level is sufficiently enough for home purposes.
Finally, I got my ICS along with some security.