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Knowledge base IPv6 NAT64 gateway

As well as IPv6 we also provide a NAT64 gateway which customers can use.

What is a NAT64 gateway

A NAT64 gateway is a service we offer that allows you to run a network that is entirely IPv6 or mostly IPv6 - connecting to the IPv4 internet using IPv6 addresses.

It consists of two parts: A DNS resolver that provides fake responses for any host that has an IPv4 address but not an IPv6 address, and a gateway that maps those fake IPv6 addresses in to the IPv4 world.

How to use it

To use the NAT64 gateway simply set your DNS resolvers to 2001:8b0:6464::1 and 2001:8b0:6464::2. If you have to use IPv4 resolvers you can also use 217.169.20.26.

Does it work

Yes, it works, and even works for fragmented packets, pings, and traceroute. As you can see, this traceroute starts on an IPv6 address then goes in to the IPv4 world.

Example traceroute traceroute to 2001:8b0:6464::212.58.246.161 (2001:8b0:6464::d43a:f6a1), 30 hops max, 40 byte packets 1 tagless.mh.aa.net.uk (2001:8b0:0:31::51bb:1ffc) 0.855 ms 1.742 ms 2.928 ms 2 eclink.a.homeless.aa.net.uk (2001:8b0:0:31::51bb:1ffa) 4.558 ms 5.747 ms 6.934 ms 3 a.armless.thn.aa.net.uk (2001:8b0:0:53::5a9b:3506) 9.543 ms 10.704 ms 11.722 ms 4 nat64.discard.me.uk (::90.155.46.46) 14.075 ms 15.261 ms 16.450 ms 5 a.armless.thn.aa.net.uk (::90.155.53.6) 17.885 ms 19.121 ms 19.922 ms 6 rt-lonap-a.thdo.bbc.co.uk (::193.203.5.90) 166.903 ms 146.365 ms 127.846 ms 7 ::212.58.238.153 (::212.58.238.153) 3.985 ms 5.800 ms 6.089 ms 8 te12-1.hsw1.cwwtf.bbc.co.uk (::212.58.239.234) 8.484 ms 9.363 ms 10.800 ms 9 ::212.58.255.12 (::212.58.255.12) 11.818 ms 14.267 ms 15.484 ms 10 fmt-vip04.cwwtf.bbc.co.uk (::212.58.246.161) 16.504 ms 17.851 ms 20.119 ms

What customers say

Quote from Bunter Such is my confidence in the IPv6 to v4 gateway that I have now moved to issuing 2001:8b0:6464::1 as the primary resolver for all three PCs on my premises. One machine is configured without a v4 stack and has been operating in this condition since February. I am regularly and successfully using IMAP-with-SSL and NNTP to v4-only hosts. The only major issue that I have identified is with inbound SIP through call.me.uk. The request for an AAAA returns a 6464 address which works fine for registration and outbound calls but fails for inbound SIP. Not a NAT 64 issue I grant, since I am informed that Asterisk is v4-only. Other than that, everything Just Works and my partner is blissfully unaware that her iPlayer streams are being NATted and delivered via v6. The next step is to shut-down DHCPv4 on my router, hopefully within the next two weeks or so, and erect an "IPv6 Only" sign at the entrance to the house. :) Thank you for a great service!