How to prevent a DNS Leak in Mac OS X

While using VPN in OS X and ISP’s (Internet Service Provider) DNS there is a risk of de-anonymization, so it’s necessary to prevent a DNS leak.

Viscosity users are able to apply the built-in solution. For Tunnelblick use the follow guide:

    1. Go to “System Preferences”:

    1. Choose “Network” in “Internet & Wireless” section:

    1. Go to “Advanced”:

    1. Go to “DNS”.


Set “Off” for “Configure IPv6”. Or if VPN service supports IPv6 keep it as “Automatically”.

    1. Remove all addresses from the list of DNS servers. Add an non-existent DNS address – Instead of this address you can set up Google Public DNS address –


With enabled IPv6 support set up 0:0:0:0:0:0:0:42 as non-existent IPv6 address or 2001:4860:4860::8888 (Google Public DNS).

From now ISP’s DNS will not be used.