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ispcolohost
New Member
October 18, 2016
Question

Possible to do site to site VPN for ipv4 & ipv6 with only ipv4 service in between?

  • October 18, 2016
  • 2 replies
  • 3618 views

Hi all, I'm wanting to give a remote site IPv6 service by way of VPN since the local ISP sucks.  I have a pre-existing IPv4 site to site (fortigate to fortigate) VPN defined with the 0.0.0.0/0 phase 2 selectors so the firewalls can do their thing themselves.  I was hoping perhaps I could set up a second tunnel for IPv6 packets by defining the same remote IPv4 destination on the remote side, a different key and different local ID so the target could tell the tunnels apart, but I'm getting a "-34: Duplicate remote gateway" error when trying to add it.

 

Is there a way around this issue?  I could easily add a second IP address on one side, but not the v4-only side.

 

Thanks

    2 replies

    Iescudero
    New Member
    October 19, 2016

    Hi There!!

     

    According to this: http://docs.fortinet.com/uploaded/files/1086/fortigate-ipsec-vpn-50.pdf (Page 173) 

     

    "...IPv6 over IPv4 The VPN gateways have IPv4 addresses. The protected networks use IPv6 addresses. The phase 2 configurations at either end use IPv6 selectors..."

     

    I never try it, but i think if you add a phase2 selector with something like this may be work (of course, you have to set address, routes and policys too):

     

    config vpn ipsec phase2-interface

    edit tunnel6_p2

    set phase1name tunnel6

    set proposal 3des-md5

    set src-addr-type subnet6

    set dst-addr-type subnet6

    end

     

    In page 183 in the same doc you have an example :)

     

    Hope it helps!

     

     

     

    ispcolohost
    New Member
    October 19, 2016

    Thanks so much; your tip got me to a working config.  I didn't realize you could have an ipv4 and ipv6 phase 2 side by side on the same phase 1.  I simply added a new phase 2 and everything began working.  I was trying to add a duplicate phase 1 with different settings previously.

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