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Unblock Us Security

Unblock Us is an interesting solution to viewing region locked content online. Instead of offering VPN services, they offer a DNS-based solution. By using their DNS servers, geolocation requests by services such as Hulu and Pandora are directed through a geographically appropriate proxy. The remainder of your traffic (e.g. the video or audio stream) is accessed directly. That means you can make use of your connection's full bandwidth. Conversely, VPN connections often decrease your connection speed significantly.

However, the DNS solution has security implications. As a DNS provider, Unblock Us is the in perfect position to perform a man in the middle attack. After all, that's what they're doing to sites like Hulu. (Note that SSL connections are safe from man in the middle attacks.)

If you trust Unblock Us, then this isn't a problem. If you don't, it's best to limit the traffic that uses their DNS servers. The remainder of your traffic should use a trusted DNS provider instead (e.g. Google's public DNS servers).

One way to accomplish this is to set up a local DNS server and configure it to forward requests appropriately. On Ubuntu, this is relatively straight forward:

sudo apt-get install bind9
sudo vim /etc/bind/named.conf.options /etc/bind/named.conf.local
Change /etc/bind/named.conf.options to use some default DNS servers (e.g. Google DNS) and to only listen on loopback interfaces:
forwarders {
  8.8.8.8;
  8.8.4.4;
};

listen-on-v6 { ::1; };
listen-on { 127.0.0.1; };
Then change /etc/bind/named.conf.local to use the Unblock Us DNS servers for the zones you're interested in.
zone "hulu.com" {
  type forward;
  forwarders {
    208.122.23.22;
    208.122.23.23;
  };
};
Finally, sudo /etc/init.d/bind restart and change your connection settings (e.g. via Network Manager) to use 127.0.0.1 as your DNS server.

Assuming you've set up your Unblock Us account, accessing hulu.com should now use the Unblock Us DNS server and direct you through their proxy. Accessing anything else should use Google's public DNS servers.

This post was inspired by Jonathan Tullett's post.

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