Dynamic DNS for both IPv4 and IPv6 (using freedns.afraid.org or others)

Question

[Edit: I have now found a solution; see below for my answer]

I want to set up dynamic DNS on my Fritz!Box 7490, so that it is reachable both on IPv4 and IPv6. Note that I want to reach the Fritz!Box itself, and not a computer behind it.

The scenario is that I have both native IPv4 and native IPv6 as dual stack, and both IPv4 and IPv6 are dynamically assigned by my ISP.

I am currently using freedns.afraid.org but would be open for other services as well if what I want can be achieved.

The issue I am facing is that the Fritz!Box GUI only allows for one update URL. In that update URL, I can use one of these three options:

• Automatic IP address detection (which uses IPv4): http:⁄⁄freedns.afraid.org⁄dynamic⁄update.php?MY-SECRET-TOKEN
• Pass IPv4 address to freedns.afraid.org: http:⁄⁄freedns.afraid.org⁄dynamic⁄update.php?MY-SECRET-TOKEN&address=<ipaddr>
• Pass IPv6 address to freedns.afraid.org: http:⁄⁄freedns.afraid.org⁄dynamic⁄update.php?MY-SECRET-TOKEN&address=<ip6addr>

However, what I would need is a link that updates both the IPv4 and the IPv6 address at the same time.

I have seen Dynamic DNS at freedns.afraid.org using a Fritz!Box - this helped as it showed me the <ip6addr> tag, but the person asking the question only wanted to update the IPv6 address, so it is not applicable to me.

Solution 1

Answering my own question as I have now found a solution.

I am now using the service nsupdate.info, which supports what I want: Both IPv4 and IPv6 are reached using the same name, for which both A and AAAA records are provided.

They had specific instructions for the Fritz!Box, which were shown when I was setting up my account. I repeat here what I have in my Fritz!Box settings now:

Dynamic DNS provider: User-defined

Update URL: https://ipv4.nsupdate.info/nic/update https://ipv6.nsupdate.info/nic/update

Domain name: mydomainname.nsupdate.info

User name: mydomainname.nsupdate.info

Password: [as provided by nsupdate.info]

I have been using this service for just over half a year now, and it works flawlessly so far (but I am not logging into my Fritz!Box daily, so your mileage may vary). Apologies for not replying earlier, but I completely forgot about this question, and just received a reminder e-mail as someone else wrote a comment.

Hope this helps others!

Solution 2

The answer is very simple: you just have to enter both update URLs with one blank in between:

https://freedns.afraid.org/dynamic/update.php?[MY-SECRET-TOKEN4]&address=<ipaddr> https://freedns.afraid.org/dynamic/update.php?[MY-SECRET-TOKEN6]&address=<ip6addr>

Works with my FRITZ!Box 7390.

Solution 3

First of all, I think it is a really stupid idea to give people dynamic IPv6 addresses. Those IPv6 addresses are used in people's internal networks, and changing them all the time makes it really hard to do manage them.

The difference between IPv4 and IPv6 is that you probably only have one IPv4 address. This address belongs to the Fritz!Box, which uses NAT to allow systems on the LAN to access the internet. With IPv6 every system has its own IPv6 address(es). In that situation it might be easier to have every system register their own IPv6 address in the dynamic DNS. It then of course depends on the system if they can actually do that...

Comments

[Michael Hampton]

Is the ISP actually changing your IPv6 prefix? Ever? They should not be doing that.

[Martin Elb]

It is the standard in Germany. People are very concerned with privacy here so they don't want to be tracked across days even when deleting cookies. The big ISPs, in particular Deutsche Telekom, therefore make IPv6 available with a dynamically changing prefix. As I said, I don't really mind but I can understand the concern.

[Michael Hampton]

I suppose if privacy conscious people really want that, then it should be an option, but it should not be on for everyone by default! This is significant breakage and makes the local network very hard to manage.

[Boris]

The documentation states that you can specify multiple update-urls in the field "If the update request is to be performed for both IPv4 and IPv6, both requests are written in this field separated by a space.". However when I tried it it doesn't seem to work. But you could give it a try too.

[Martin Elb]

Thanks, Boris. This is actually what I am doing now with a different provider though (it may also have worked with freedns.afraid.org). See below for my answer.

[Martin Elb]

Thanks a lot. To clarify, I don't want to reach a computer behind the Fritz!Box, but I want to access the Fritz!Box itself. You will also find many people that prefer dynamic IPv6 prefixes for privacy reasons (personally, I don't care so much, but I understand the argument). Finally, you can use local, non-routable static addresses in your internal network; a computer can have many IPv6 addresses assigned to it.

[Sander Steffann]

True, ULA is an alternative for traffic that doesn't leave the local networks next to the global unicast addresses from the ISP.

[fixer1234]

If you're not sure, yet, of the results, the answer may be premature (and might attract downvotes since it isn't a definitive solution). You might want to delete it until you are ready to post something solid. Deletion will hide it here, but it will be visible to you and you can edit it and then undelete it when you're ready.

[Vlastimil Ovčáčík]

Welcome to SuperUser, please use code formatting (Ctrl+K) on snippets.

[ede-duply.net]

6 years later still works on a fritzbox 7412 as well! take care to use the correct secret tokens as using the wrong one will "autocorrect" the dns entry type (A<->AAAA)