Here is my question : I got 2 websites ; one 192.168.1.1 and other is 192.168.1.2 , google will care them when they are linking each other or I must have totally different block? Thanks
Google won't care, they might even pass some PR, However, DO NOT create a whole network of websites with the intention on linking to one another, Google will catch on and may even penalize your sites for it
It's best to diversify IP's.. Google "linkwheel" for more info. It would be trivial for G to keep track of the IP's linking to a site and penalize if they're all coming from the same place (or even a significant amount of them)....