1. How can we redirect the ip which is browsing the restricted websites to the desired page. Though our program blocks the website but it is unable to redirect the page.
You can’t redirect connections using existing LNM API, it would require an additional kernel level extension. Actually redirects are far easier implemented using WinpkFilter.
2. We connected two PC via LAN wire and gave internet connection to one of them(gateway). We are accessing the internet on another PC via the previous one. But the data of the non-gateway PC is encrypted and hence we are unable to monitor its requests.
The only correct way I can see is installing your software on gateway system and monitoring the Internet connection with WinpkFilter. LNM API does not have access to the routed packets.