I am using OpenWRT router. I need to block a URL or multiple URLs (Not IP) for specific time. for example, I want to block facebook.com so that clients of this router cant access the website. firewall rules should have the option to do that but I dont know how to do that.
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Here is one way to block by domain name rather than by IP address.
The main reason of why you need such a complicated method is that each domain name (e.g. facebook.com) may be resolved as different IP address at any given time. So, we need to keep a list of resolved IP addresses and add iptables rules based on this list.
First, you should enable logging in dnsmasq config:
uci set dhcp.@dnsmasq[0].logqueries=1
uci commit dhcp
/etc/init.d/dnsmasq restart
This will give you log entries like:
daemon.info dnsmasq[2066]: reply facebook.com is 31.13.72.36
Now, you just have to constantly parse syslog and add corresponding iptables rules like this (note that you most likely need a more versatile script and ipset for better performance):
logread -f | awk '/facebook.com is .*/{print $11}' | while read IP; do iptables -I OUTPUT -d $IP -j DROP; done

Vasily G
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I have got another option to do that instead of directly accessing iptables. We can use proxies. tinyproxy might be a good choice. – Raihanhbh Oct 19 '16 at 04:13