There are various ways by which you can block any website from opening in your network.
This is based on the fundamental of blocking the request of any URL from inbound traffic. If you are using any antivirus or firewall, you can implement blocking rules into it. For example if you want to block any website, you have to write rules on the firewall.
For Windows Firewall follow these steps:
go to Control Panel > windows Firewall > in the left side click Advanced Setting
go to Outbound Rule and in right side Click New Rule in New Outbound Rule Wizard select Custom and click Next in Program Screen Select All Program And click Next in protocol and ports Leave default Setting and click Next in Scope Screen Under Which remote IP address Does This rule apply to? select These IP address and click add Button
in IP Address Dialog under This IP address or subnet: enter IP address of website and click ok and then click next in Action screen select Block the connection and click next
in Profile screen leave all 3 check box selected and click nextin Name Screen choose name for rule and click finish test what you do by enter URL in any browser that you want good luck!