6in4 questions

I’m having some concerns about my attempt at establishing a ?working? 6in4 tunnel. Frankly, I’m finding myself IOMH.

  • first attempt to establishing the tunnel leads me to CGNAT fail establishing a tunnel on my ISP assigned 100.x.x.x WAN net block - what else can I try?

  • well, let’s try on WG upstream -
    and sure enough up comes the tunnel, I add the /48 and ip6 assigns, and everything SEEMS normal/working. Clients get ip6 apparently from the /48, and for all attempts and purposes everybody is good ip4/ip6.

  • OK, does it work on the VPN? Seems to? All clients with ip6/ip4, basic diags pass, and again, all seems normal.

  • Netflow sensors are also seeing the ip6 traffic

I tend to be dangerous at times to myself. To wit,”am I missing something?”, any pitfalls? Don’t do?

6in4 requires protocol 41 being accessible from the outside (over IPv4), that is not possible behind any form of NAT. I guess that might also catch you with your VPN workaround, as you need to forward protocol 41 traffic that way as well.


That’s my question. I really didn’t think I could establish a tunnel via WG or VPN, but I can on both per HE, and everything works?

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Got a bone for an old dog? As I said, I’m in over my head. I think you know they fail ip6 tests, but what gives?

I didn’t think this would work straight up due to cgnat, but HE tells me it’s OK using WG/VPN endpoint via the cert (Explorer) test. So I started playing. I can ping6 to local clients/internet, VPN-PBR reflects the ip6 service gateways . . . Just trying to get a leg up on this.

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Looks like all is good - forget to fire up the 6in4 tunnel again before trying yesterday :tired_face:

So - can my setup compromise me? Or can I strike my get IPv6 up and running job jar off my list?

I’m guessing not?

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The browser default is detected as IPv4, but it's supposed to be IPv6.
This can be a sign of using ULA+NAT6 instead of the proper GUA prefix.
Or it's just a temporary issue and restarting the browser should solve it.

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Thanks! Browser reset fixed that.

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