Saturday, June 18, 2011

IPv6 6over4 tunnels with Windows and Cisco

Repost from old blog
A few years ago I began working with Art Shelest here at Microsoft to get Native IPv6 running in my lab.  After a few weeks we had it up and running. 
We had to work with MSIT (was known as ITG at the time) to get a 6over4 tunnel setup so that we could connect to the 6bone even though my upstream routers did not support IPv6 (still don't at this time).  Once the tunnel was setup on the ITG Router we ran a command on my Windows IPv6 Router in my lab and it was up and running. 
We run our entire lab IPv6 network on Windows Routers.  We use Windows Server 2003 but you could use Windows XP Pro if you wanted.  Unlike RRAS the IPv6 routing stack is included in Windows XP.  And after Windows XP SP1 this stack was fully supported by Microsoft support.  So if you follow the steps at you can get your internal test network setup.
Now to create a 6over4 tunnel to another router you simply run the below commands from a cmd prompt on your main IPv6  router
  1. netsh
  2. int ipv6
  3. add v6v4tunnel interface="V6v4 Tunnel" localaddress=<local ipv4 address> remoteaddress=<remote ipv4 address>
  4. set interface "v6v4 Tunnel for=en
  5. add address int="v6v4 tunnel" address=<IPv6 address from provider>
  6. add route ::/0 "v6v4 tunnel" <remote IPv6 address> publish=yes
Key things to note with the above
  • The Local IPv4 address is the IP address that the tunnel is going to use to talk to the Upstream V6 Router (With my example below it would be 
  • The Remote IPv4 Address is the IP address of the upstream V6 router (with my example below it would be
  • The IPv6 address from provider would be a IPv6 address that you get from your v6 provider (with my example below it would be 3ffe:ffee:100:2::2)
  • The Remote IPv6 address is the IPv6 address of the upstream IPv6 router (with my example below it would be 3FFE:FFEE:100:2::1)
The Cisco side of the config looks like this
interface Tunnel1
 description v6in4 tunnel to  lab
 no ip address
 ipv6 address 3FFE:FFEE:100:2::1/64
 tunnel source
 tunnel destination
 tunnel mode ipv6ip

Once the machines are all setup important things to know are "how do you back up your ipv6 configuration?" Well with netsh it could not be easier.
Simply run 'netsh int ipv6 dump > c:\ipv6backup.txt'  this will dump all the ipv6 config out to the txt file.  Now if the router was to ever go down you can run the command  'netsh exec c:\ipv6backup.txt'.   With these 2 commands it will backup and restore your ipv6 configuration..  You can also modify the backup command to be 'netsh dump > c:\netshbackup.txt' and it will back up 99% of all the settings for your network configuration.
If you would like to know more about how I have my IPv6 network setup please let me know.  Also I recommend the Microsoft Press Book Understanding IPv6 ( ISBN: 0-7356-1245-5

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