It might seem quite strange to think that the Domain Name System, actually plays a role in filtering and region locking however it is actually true. In fact DNS has been used extensively on both sides of the battle both for blocking access and bypassing content filtering. It’s most extensive use is historically as a very blunt weapon to block access to websites.
Many countries still use DNS poisoning/spoofing in order to block access temporarily to specific sites. Turkey for example still periodically uses DNS to stop people accessing social media sites, supposedly in the ‘national interest’. It’s quite simple to do, you just modify the DNS records of the sites at the major ISPs in the country. So instead of Facebook resolving to the true IP address it is routed through to a government server instead. It’s a simple method and fairly effective although easily bypassed by using a trusted DNS server instead of the modified ones.
However on the other side of the coin, perhaps more surprisingly you’ll find DNS used to bypass region blocks. What happens is that you use ‘Smart DNS’ servers to effectively make decisions to route traffic. For example many people use a Smart DNS Netflix system to enable access to different regions of the Netflix media sites. All the server does is route the connection through the appropriate country before accessing the Netflix website. SO if you want to use American Netflix you’ll be routed through a US based server – through a British one for UK Netflix and so on.
The advantages of using DNS in this situation is that you only route when absolutely necessary unlike a VPN. The other significant bonus is that it’s simple to modify DNS settings on any device, without the requirement of installing software on the client. This means you can use Smart DNS on TVs, Tablets, games consoles and media streamers simply by accessing the network settings and specifying the modified DNS servers.
Return of US DNS Netflix, Techno Press, 2015