[OpenVPN home] [Date Prev] [Date Index] [Date Next]
[OpenVPN mailing lists] [Thread Prev] [Thread Index] [Thread Next]
Web openvpn.net

[Openvpn-users] Active IPv4 VPN connection affects native IPv6 connectivity

  • Subject: [Openvpn-users] Active IPv4 VPN connection affects native IPv6 connectivity
  • From: "Jason R. Coombs" <jaraco@xxxxxxxxxx>
  • Date: Mon, 29 Oct 2007 06:51:04 -0600

I'm using OpenVPN 2.1 RC4 on Windows Vista 64-bit.  I also have configured a

6to4 IPv6 internet address through an auto-configured tunnel broker.  With 
OpenVPN disconnected, I can browse to www.kame.net or www.showmyip6.com and
will indicate that I am connecting through my IPv6 address.

When I connect the OpenVPN connection, I can no longer browse using IPv6.  I

can still ping IPv6 hosts and connect to the hosts by explicitly connecting
the IPv6 address (e.g. http://[2001:200:0:8002:203:47ff:fea5:3085]/ ). 
However, if I merely enter the DNS name, I only connect to the IPv4 host.

Therefore, I don't believe it's a routing issue, but a IPv6 preference

To get IPv6 browsing to work via the 6to4 address (without OpenVPN), I had
adjust the prefix policy for windows to use the following:

C:\>netsh interface ipv6 show prefixpolicies
Querying active state...

Precedence  Label  Prefix
----------  -----  --------------------------------
        50      0  ::1/128
        40      1  ::/0
        30      1  2002::/16
        20      3  ::/96
        10      4  ::ffff:0:0/96
         5      5  3ffe:831f::/32

In particular, I had to change 2002::/16 to have a label of 1 and I replaced

the teredo prefix (2002::/32) with 3ffe:831f::/32.

So, it seems OpenVPN is affecting the preference for IPv6, but I can't tell 

Has anyone else experienced this behavior?  Any suggestions?


Attachment: smime.p7s
Description: S/MIME cryptographic signature