The Zeroshell is one of most popular open source router I have ever found. It provides bunch of features such as DNS, DHCP, proxy server facilities like Squid Proxy and Firewall facilities. Here I’m going to share how to restrict particular sites for LAN users using ZeroShell built-in firewall. This method can be used to restict group of the web sites by matching string pattern which contained on domain name. For an instance you block all domains which contain string of “gossip” inside of  your LAN . Let’s go thorough quickly, steps of blocking websites using Zeroshell

1) Open Zeroshell Firewall window

GO “SECURITY” –> “FIREWALL”

2) Select “INPUT” chain

3) Click “Add” to make a new rule

4) Configure new firewall rule

This example gossiplanka9.info domain will be going to block.you should replace your string value here.

Source ip :- host which is going to be blocked, you can define source range if you wish
Destination ip :- Default gateway (Zeroshell proxy LAN interface ip)

IPTABLES Parameters :-  -m string –algo kmp –string gossiplanka9.info
ACTION :- DROP

5) Save the rule

Don’t forget to SAVE, otherwise nothing will happen.