An easy way to circumvent OPENDNS

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colinsw

January 08, 2014 21:20

There is an easy way to get around opendns that I need to block. 

I've set opendns on the router and it all works fine, but 8888 4444 in the machine's dns allows the user to circumvent opendns. It's really easy to find a tutorial on this as well (http://www.wikihow.com/Bypass-OpenDNS-Internet-Security) 

I work in a school and we lock the machines down using windows group policies - but lots of the kids bring their own machines - which I can't lock down. 

Any thoughts on what I can do about this would be REALLY appreciated.

 

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  cindelicato January 09, 2014 00:44

  You can create a rule on the school firewall to restrict PORT 53 that would enable only OpenDNS.

   

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  rotblitz January 09, 2014 13:00

  Or better: configure your DHCP server to give out only your internal DNS server's IP address(es) (which has OpenDNS as forwarding configured), and block port 53 passthrough outbound as cindelicato said.

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  pneumoman May 21, 2014 12:30

  Many thanks for this. Now I realise how my sons school laptop has been bypassing our OpenDNS proxy.

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  Kristy Patullo May 21, 2014 12:33

  We also have a support article detailing how to use firewall rules to prevent the circumvention of OpenDNS: https://support.opendns.com/entries/26374985-Preventing-circumvention-of-OpenDNS-with-firewall-rules

  Additionally, if you make yourself the administrator of devices on your network other users won't be able to change the DNS settings of these devices to bypass OpenDNS.

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