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Bypassing OpenDNS Blocks

Introduction

OpenDNS provides a worldwide free DNS service. When you try to visit a domain name, such as philproxy.com, your computer queries an OpenDNS DNS server which will then return the IP address of the domain, something like 125.5.114.62.

How does OpenDNS block sites?

OpenDNS, or any DNS based filtering/blocking service for that matter blocks sites by returning fake information when your computer requests the IP address of a blocked domain. If you were to visit Google.com then OpenDNS would return the genuine IP address, but if you tried to access a blocked domain like Facebook.com then OpenDNS will return modified/fake data which will redirect you to block.opendns.com.

How to bypass OpenDNS blocks

There are two methods that you can use to bypass OpenDNS or other DNS based filtering/blocking service.

  • Method 1: Web Proxy
    • You can use a web proxy service like the one offered by PhilProxy.com. When surfing a blocked site like Facebook through a web proxy, your computer and DNS provider will think you're simply browsing PhilProxy.com because PhilProxy will be making all the connections to Facebook for you. There are thousands of free web proxies out there but you should ideally use one that's hosted in the same country as you for the best speed results.

    Pros: Web proxies don't require any installation of special software or modification to your computer.

    Cons: OpenDNS provides an option to block known web proxies, which can render the use of web proxies to bypass blocks ineffective. However there new proxies going live every day that OpenDNS won't immediately be aware of.

    One major con of using a web proxy is that you can't be sure of what details the web proxy site might be storing such as the login details to your email, facebook or other accounts.


  • Method 2: HOST file modification
    • Although this method is slightly more technical than simply using a web proxy, it should be within the capabilities of most users. This method involves making a temporary modification to your computers HOST file. The HOST file can be used to store the real IP address of a website that you want to visit. So when you try to visit a blocked domain, for example Facebook.com, your computer will already know the real IP address for that domain and won't waste time querying OpenDNS. Since no query is sent to OpenDNS, your computer won't receive any false data which is used to prevent your computer from accessing that domain.

    How To
    You'll be editing your computers HOST file, this means you need to have admin/root privileges.

    1) Find the IP address of the domain that you want to access.

    2) WINDOWS VISTA/WINDOWS 7
    Click on Start -> Accessories -> right click on Notepad, Run as Administrator. A notepad will open which has administrator privileges. Click File -> Open and browse to c:\windows\system32\drivers\etc\ and open the file named hosts.

    Create a new line at the bottom of this file. The line should have the IP address that you collected in Step 1, a space, and then the domain that the IP address belongs to. For example you might enter
    69.63.181.11 www.facebook.com


    2) MAC OS X
    Click on Spotlight (top right of your screen) and type in the word terminal. Clicking on the top hit should now launch a terminal window.

    In the terminal, type sudo /Applications/TextEdit.app/Contents/MacOS/TextEdit /etc/hosts and hit return. Enter your password when prompted. Note that no characters will appear when you're typing your password. Simply hit return once you've entered your password.

    Your HOSTS file should have loaded into TextEditor. Create a new line at the bottom of this file. The line should have the IP address that you collected in Step 1, a space, and then the domain that the IP address belongs to. For example you might enter
    69.63.181.11 www.facebook.com


    2) LINUX(i.e. UBUNTU)
    Click on Applications, accessories and then terminal.

    In the terminal, type sudo gedit /etc/hosts and hit return. Enter your password when prompted. Note that no characters will appear when you're typing your password. Simply hit return once you've entered your password.

    Your HOSTS file should have loaded into a text editor. Create a new line at the bottom of this file. The line should have the IP address that you collected in Step 1, a space, and then the domain that the IP address belongs to. For example you might enter
    69.63.181.11 www.facebook.com


    3) After modifying and saving the file, you should be able to browse the blocked site without any further modification. If you tried to visit the blocked site before performing this modification then it's possible that your browser has temporarily cached the false IP address for the blocked domain. Usually restarting your browser will clear its DNS cache.

    Pros: You'll experience high speed browsing without the delays experienced with web proxies.

    You don't need to worry about the privacy of your data since it's not passing through a third party proxy.

    Cons: You need to have an admin account on the computer to make these modifications.

    Side comment: If you have an admin account on the computer then you could most likely change the DNS servers that your computer is using. So instead of going via OpenDNS you could tell your computer to use another provider like Google public DNS. This would also be an effective method of bypassing the OpenDNS blocks.