The above noted you can do the following stuff.
Back to the point: parental control. I have kids at home and all sorts of networked devices: smartphones, tablets, computers, servers, printers, you name it. I want to be able to disable adult site browsing and the like from kids hardware. The easiest solution I found so far is OpenDNS (
http://www.opendns.com), which offers you free DNS filtering for one IP address. Create an account, configure your home IP address, set the categories you want to ban, and done. Any machine on my internal network using OpenDNS will receive re-directs for unwanted sites. In the past I used to manually modify the DNS settings on all kids hardware to switch to OpenDNS servers, but that quickly becomes old, and sometimes requires some sleight-of-hand to configure. Forget it.
Enter OpenWRT: you can actually assign different DHCP settings to hosts on your network, e.g. different DNS servers. Even if the documentation is respectfully thick on that topic, it took me a while to understand it.
Procedure:
1. edit /etc/config/dhcp to add a new section
config tag 'kids'
list dhcp_option '6,208.67.222.222,208.67.220.220'
2. Now add individual sections for all devices you want to include in the ‘kids’ section:
config host
option name 'pluto'
option mac 'YOUR DEVICE MAC ADDRESS'
option ip 'YOUR DEVICE ADDRESS ON THE INTERNAL NETWORK'
option tag 'kids'
3. Restart dnsmasq with: /etc/init.d/dnsmasq restart
And you are done. Just tag the hosts you want to be part of the kids zone to distribute the OpenDNS servers instead of the default one.
https://nicolas314.wordpress.com/2014/12/10/parental-control-with-openwrt-and-opendns/
A little bit about DNS hijacking in general.
DNS hijacking or DNS redirection is the practice of subverting the resolution of Domain Name System (DNS) queries. This can be achieved by malware that overrides a computer's TCP/IP configuration to point at a rogue DNS server under the control of an attacker, or through modifying the behaviour of a trusted DNS server so that it does not comply with internet standards.
These modifications may be made for malicious purposes such as phishing, or for self-serving purposes by Internet service providers (ISPs) and public/router-based online DNS server providers to direct users' web traffic to the ISP's own web servers where advertisements can be served, statistics collected, or other purposes of the ISP; and by DNS service providers to block access to selected domains as a form of censorship.
http://en.wikipedia.org/wiki/DNS_hijacking