An easier way (for many users) to disable IPv6 leakage (as per the discussion above, and probably advisable for anyone who hasn't done it yet) would be to do the following:
For Windows Vista and above:
Open cmd prompt and type:
netsh interface teredo set state disabled.
For Ubuntu (10 and up):
Copy and paste the following lines into a terminal one at a time (enter / return after each line, so you can see the result after each time you've entered a command):
echo “#disable ipv6″ | sudo tee -a /etc/sysctl.conf
echo “net.ipv6.conf.all.disable_ipv6 = 1″ | sudo tee -a /etc/sysctl.conf
echo “net.ipv6.conf.default.disable_ipv6 = 1″ | sudo tee -a /etc/sysctl.conf
echo “net.ipv6.conf.lo.disable_ipv6 = 1″ | sudo tee -a /etc/sysctl.conf
FWIW, this works for Ubuntu 14.04 LTS.
This does not include OSX or iOS instructions, so...
from http://www.vpnfan.com/blog/how-to-disab ... ndows-mac/
To disable IPv6 in Mac OS X Yosemite (10.7 or 10.8) you will want to start by going to Applications, then Utilities, and finally click on Terminal. You can get a list of your network interfaces by issuing the following command:
Most newer Mac’s only have wi-fi network interfaces. Running the command above will list a LAN interface if you have one. Now you will want to issue these commands to disable IPv6:
networksetup -setv6off Wi-Fi
networksetup -setv6off Ethernet
There is a more comprehensive list for OSX users (10.7.x, 10.8.x, 10.9.x, and 10.11.x) on how to disable IPv6 here:http://help.unc.edu/help/how-do-i-disab ... -mac-os-x/