The trick with content filtering with DNS is where the DNS provider categorizes each website into topics like politics, phishing, alcohol or porn. Then you get to select which categories you want to let through. So when you say to filter out all porn sites, it will not give out those IPs (phone number) to any device on your network be it a iPod, laptop, phone or tablet!
Now, no technology is foolproof and this is no exception. It can be bypassed in one of these three ways:
- If you already know the IP address you can type it in directly.
- There is a way to reconfigure a laptop to use specific DNS servers.
- They can go to someone else's house that does not have these sites blocked.
Also, this does not block site like YouTube where you can find almost anything. But it does take care of the dedicated sites. There are several providers out there - most are free - but I chose OpenDNS because it was the largest and easiest and free!
The first step is to go to OpenDNS and setup an account. They also have instructions on how to configure your router (better than mine).
Next you have to go to your router's configuration page and enter OpenDNS's IP addresses into your DNS server fields. This is where you put it in DD-WRT:
Be sure to click save/apply, and some routers may require rebooting. All devices on your network will get the new DNS server IP addresses then next time they restart.
Now, there's one more step. The same way laptops and tablets get a new IP address every time they connect to your network, your network might get a new IP address when connecting to your ISP. The problem is that your LAN's IP address is how OpenDNS knows what your preferences are. So, in order for OpenDNS to know what your preferences, you must keep your IP address updated in their system. Painful? No!
Go to OpenDNS' site and down load the Updater. It's a simple little application that runs on one of your laptops and periodically checks in with OpenDNS to tell them your network's IP address. I suggest installing it on a laptop you use frequently. Or, if you have DD-WRT on your router go here and follow their instructions on how to configure your router to do it - very elegant!