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How to prevent IPv6 leaks under Linux, using OpenVPN?

leak linux ipv6 openvpn

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#1 ChrisHoot



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Posted 05 July 2017 - 10:34 AM

Hi all,

I've followed the instructions at https://airvpn.org/topic/11431-using-airvpn-with-linux-from-terminal/ in order to set up my account. This works fine and leak-free, when my local networks gives me an IPv4 address -- but if I get an IPv6 address, that address is leaked to remote sites according to https://ipleak.net/ . How do I prevent that?

Thanks, Chris

#2 nick75


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Posted 05 July 2017 - 09:03 PM



See here to disable IPv6.

#3 air-fun



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Posted 06 July 2017 - 05:25 AM

​Or try add this parameter to end of kernel boot line:


#4 cm0s


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Posted 06 July 2017 - 06:02 AM

say yer drive is incrypted your grub would look like this:

GRUB_CMDLINE_LINUX="cryptdevice=/dev/sda3:cryptroot ipv6.disable=1 video=1360x768"


then recheck/build...
# grub-install --recheck /dev/sda
# grub-mkconfig -o /boot/grub/grub.cfg


if you do an ip link command or ifconfig and don't see ipv6 addr good sign

here's another link for debian ubuntu etc:




arch basically above but more info:



same info but mohr detail as above:



iptables stuff:



#5 Staff


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Posted 06 July 2017 - 10:17 AM



disabling IPv6 might be too problematic in some circumstances, and in general it's an overkill solution.


Setting two or three ip6tables rules is a much more practical approach, and of course it is faster, you just need a second. Network Lock feature does that, in case you run Eddie for GNU/Linux.


Kind regards

#6 ChrisHoot



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Posted 08 July 2017 - 12:49 PM

Thanks, I'll try the sysctl thing the next time I'm in such a network. Or ip6tables, if that doesn't work.

#7 cstreet



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Posted 16 October 2017 - 06:59 PM

Activating the AirVPN "network lock" does stop my ISP IPv6 address from showing up on ipleak.net ... but I can't use Thunderbird to fetch email with the network lock activated.


So I tried disabling IPv6 in Firefox (1. "about:config" in url address box; 2. "network.dns.disableIPv6" in search box; 3. double tapping (or clicking) to change default of "false" to "true").  That seems to work fine, as ipleak.net shows "IPv6 test not reachable."


But does this mean that:  -A. my IPv6 address is still leaking, and I'm just not seeing it in Firefox because IPv6 is disabled; or -B. that Firefox is actually stopping my IPv6 address from being shown on the web?


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