Which DDNS services support ipv6 address updates?

[AndrewL733]

My mobile phone provider (T-Mobile) seems to be causing issues for accessing my home via any VPN. While in the past when I was on Sprint, I could use OpenVPN from my phone to my house, now that I'm on T-Mobile, I'm not passing any data through the VPN. I connect okay -- both the ASUS RT-AC86U and the OpenVPN client on the iPhone show I'm connected -- but I can't ping or open web pages on my home network from my phone. I have the same issue with ZeroTier (in this case, ZeroTier is running on a separate computer in my house).

I was able to "solve" the OpenVPN problem by enabling "IPV6 Passthrough" on the ASUS router. (By the way, I'm on asuswrt-merlin 386.11). The ASUS Router shows it has a public IPV6 address, and if I "override" the server address in the OpenVPN iPhone client by entering the router's IPV6 address, OR if I manually enter the router's IPV6 address in my DYNDNS.ORG hostname record on their website -- either method works -- now when I connect from my phone, I am able to access all resources on my internal network. Web pages VNC instances, etc. I'm not 100 percent sure why this all works, but I'm happy it does.

Now my problem is, XFINITY (my ISP) is not guaranteeing that I'll always have the same IPV6 address, and the DDNS service on asuswrt-merlin doesn't seem to update IPV6 addresses automatically if they change. In fact, the DDNS services seem to ignore IPV6 altogether. Is there a reasonable solution here?

 

[glens]

Why would the address change? I thought the main purpose of V6 was enough addresses to go around - thus no need for NAT.

Have you experienced an address "change" situation with Xfinity or are you just prepping for the possibility?

 

[AndrewL733]

Hi @glens. I too assumed the IPV6 address would remain constant but I called Xfinity tech support to ask and they said "it will change from time to time". It's possible the guy had no idea what he was talking about. As I only just enabled IPV6 yesterday, I haven't seen any changes yet. Maybe it's not going to be an issue. Just don't want to find out at an inconvenient time.

 

[glens]

I'll bet that whenever your IPv4 address changes "from time to time", the IPv6 addy don't...

 

[RMerlin]

I'll bet that whenever your IPv4 address changes "from time to time", the IPv6 addy don't...

Depends on the ISP. In my case, my ISP by default will assign a dynamic /64 that can change at any time. If you ask them, they can delegate you a static /56, for you to subnet as you wish.

 

[sfx2000]

Gah - TMobile Home Internet, where do we start... and TMHI is very similar to what you'll see with their mobile phones, as it's essentially the same approach.

1) all inbound ports are filtered for both IPv4 and IPv6

2) Tmobile does not assign an IPv6 Prefix Delegation when assigning IPv6 addresses to attached clients to their gateways - they will assign IPv6 addresses from their managed pool, but as I mention, no PD is available - so it's all passthrough on IPv6

3) IPv4 is RFC1918 private addresses - e.g. you will be assigned by default a 192.168.12.0/24 address on your LAN/WLAN.

4) IPv4 is 464XLAT, which is similar to CGNAT, but different in that your IPv4 traffic is tunneled over to a PLAT end-point where many IPv4 addresses can be shared, and that end-point might be in a different geographic region

I'm not so sure about ZeroTier, as I haven't run it in a long time, but if you know the caveats as I mention above, you might be able to sort things there...

Another option might be TailScale, which is WireGuard based, but I won't guarantee that it'll be good...

(likely will be, but I won't go on record with TMHI - it does work well on my other provider, CoxHSI though)

 

[sfx2000]

Now my problem is, XFINITY (my ISP) is not guaranteeing that I'll always have the same IPV6 address, and the DDNS service on asuswrt-merlin doesn't seem to update IPV6 addresses automatically if they change. In fact, the DDNS services seem to ignore IPV6 altogether. Is there a reasonable solution here?

Can't speak for other DDNS providers, but No-IP does offer IPv6 support...

No-IP Now Offers IPv6 Dynamic DNS - No-IP Blog

What is IPv6? IPv6 is an Internet addressing system that is designed to replace IPv4. It works in a very similar way as IPv4 but offers some additional benefits. As the pool of available IPv4 addresses diminishes, there was a need to implement a protocol that offers a much larger pool of IP...

blog.noip.com

 

[Ripshod]

I would have suggested duckdns but the IPv6 resolution has been down for me 5 days - came back ~3hrs ago. Very unreliable.

 

[AndrewL733]

Hello @Logi . I honestly don't know exactly how this is working. You might want to try to install the Asuswrt-Merlin firmware if the stock firmware doesn't have the needed IPV6 setting.

In my case, I simply enabled passthrough and rebooted my router and then I could see that the router got an IPV6 address from my ISP (Xfinity, not T-Mobile. T-Mobile is my phone service provider). By the way, the only place on the router where I could see the IPV6 address was on the command line. I logged in by SSH and ran "ifconfig" and could see that for the port "eth0" I had my public IPV4 address plus two IPV6 addresses. I discovered that the router was reachable via the IPV6 address, and I added it to my DDNS record and that was that.

Here's what the ASUSWRT-MERLIN interface looks like: My SSID and IP Address blanked out.

Here's what the DYNDNS interface looks like. There's a place where you can fill in your IPV6 address.

My recommendation would be to use no-ip.com instead of dyndns. Similar setup, except with no.ip.com you have to choose between making an "A Record" or an "AAAA Record" -- the latter supporting IPV6 and IPV4 simultaneously. If you already have an A-Record for a Domain Name, you need to delete the Domain Name and recreate again as an AAAA. No big deal. The dyndns, you can modify the record type after the fact.

FWIW, the IPV6-test link you sent shows that IPV6 is not working but my PBN shows otherwise.

Hope that helps somewhat.

Andrew

 

[AndrewL733]

Oh, and just to be clear, if I set the IPV6 address in the DDNS record, I did not have to override the server address in the iPhone OpenVPN client. If I did NOT set the IPV6 address in the DDNS record, I had to enter the router's IPV6 address in the "Server Override" field in the VPN client.

 

[Logi]

Hello @Logi . I honestly don't know exactly how this is working. You might want to try to install the Asuswrt-Merlin firmware if the stock firmware doesn't have the needed IPV6 setting.

In my case, I simply enabled passthrough and rebooted my router and then I could see that the router got an IPV6 address from my ISP (Xfinity, not T-Mobile. T-Mobile is my phone service provider). By the way, the only place on the router where I could see the IPV6 address was on the command line. I logged in by SSH and ran "ifconfig" and could see that for the port "eth0" I had my public IPV4 address plus two IPV6 addresses. I discovered that the router was reachable via the IPV6 address, and I added it to my DDNS record and that was that.

Here's what the ASUSWRT-MERLIN interface looks like: My SSID and IP Address blanked out.

View attachment 54998

Here's what the DYNDNS interface looks like. There's a place where you can fill in your IPV6 address.
View attachment 54999

My recommendation would be to use no-ip.com instead of dyndns. Similar setup, except with no.ip.com you have to choose between making an "A Record" or an "AAAA Record" -- the latter supporting IPV6 and IPV4 simultaneously. If you already have an A-Record for a Domain Name, you need to delete the Domain Name and recreate again as an AAAA. No big deal. The dyndns, you can modify the record type after the fact.

View attachment 55000


FWIW, the IPV6-test link you sent shows that IPV6 is not working but my PBN shows otherwise.

Hope that helps somewhat.

Andrew

Thank you

 

[sfx2000]

Similar setup, except with no.ip.com you have to choose between making an "A Record" or an "AAAA Record" -- the latter supporting IPV6 and IPV4 simultaneously. If you already have an A-Record for a Domain Name, you need to delete the Domain Name and recreate again as an AAAA. No big deal. The dyndns, you can modify the record type after the fact.

Just want to comment here - one can have both an A and AAAA record at No-IP...

Where one might want the IPv6 AAAA record only is if the IPv4 network is NAT/CGNAT'ed...

 

[RMerlin]

Just want to comment here - one can have both an A and AAAA record at No-IP...

Where one might want the IPv6 AAAA record only is if the IPv4 network is NAT/CGNAT'ed...

We should be past these dyndns shenanigans with IPv6. Greedy and/or stupid ISPs. My own ISP assigns me a static /56, so I wouldn't need any of that if I needed remote IPv6 access.

 

[sfx2000]

We should be past these dyndns shenanigans with IPv6. Greedy and/or stupid ISPs. My own ISP assigns me a static /56, so I wouldn't need any of that if I needed remote IPv6 access.

My ISP gives me a /64 unfortunately - and it's changed a couple of times, each one after a node split (my primary broadband is cable).

It would be nice to see things settle, but many ISP's are still doing what they can to make home-based servers difficult...