Old config doesnt work

So I used to play along time ago, had no issues updating cod4x to 21.1 untill it came to joining a server. All the server names are just ip addresses and I cant join any. Couldnt find a fix untill i ranomly tried on a difference profile which worked. I then changed the config file on my originial profile and it worked. The issue is id like to use that old config, it had a really good fps boost and changed some other stuff too, does anyone have any idea what settings in the config might be causing this or how to fix it?