IPv6 Not Allowing Manual DNS Server

[nickp85]

I recently changed ISPs and the new ISP uses CG-NAT but allows IPv6 passthrough. I enabled it and my clients can get IPv6 IPs which helps get around the limitations of CG-NAT to some degree but I also use Pihole on my local network with the router configured to give out the pihole IP as DNS. I noticed since enabling passthrough IPv6, my clients are getting an IPv6 DNS server which I have not configured anywhere. I would like the clients to continue to use IPv4 Pihole and get AAAA records from it. I cannot find any way to stop this other IPv6 DNS server (I assume the router's IP or the ISP) from being sent to the local clients.

I even tried to configure Pihole with an ipv6 local static IP and set this as the IPv6 DNS server under DHCP but that IP is not being give to the client, still getting the other one that's coming from somewhere (assume ISP).

How can I use IPv6 but limit DNS to only pihole server IPv4 address?

My router is ASUS RT-AX86U PRO with latest Merlin firmware

Thanks

 

[nickp85]

Update: I was able to reconfigure to use Native for IPv6, my ISP or the router is finicky and I need to do a full reboot every time I make a change that impacts WAN even if saving the setting in the GUI does not trigger a full reboot.

I put Pihole on a static IPv6 address in the range given by my ISP that the router registered as LAN IP and then configured IPv6 DNS for DHCP to give out Pihole DNS and it appears to be working.

I still wish there was a way to simply disable IPv6 DNS and just rely on IPv4 for DNS. If I don't specify an IP, it gives out the router's address.

 

[nickp85]

Update 2: seems the ipv6 prefix given by the ISP is definitely not static. My pihole is still working but is on a different prefix than the rest of my LAN now. Whats the best way to make this work?

 

[ZebMcKayhan]

Update 2: seems the ipv6 prefix given by the ISP is definitely not static. My pihole is still working but is on a different prefix than the rest of my LAN now. Whats the best way to make this work?

Any reason you can't use dnsdirector with pihole link-local address globally, then use pihole mac and set to no redirection?

 

[nickp85]

pihole seems to get the same MAC as the Unraid server it's running on even with a custom IP. Router doesn't see it as a separate device

 

[ZebMcKayhan]

pihole seems to get the same MAC as the Unraid server it's running on even with a custom IP. Router doesn't see it as a separate device

Ok...

Have you tried putting in the link-local address of the pihole as dns server in the ipv6 page (connect to dns automatically = no)? It should remain static and is exactly for this type of purpose. But I don't know if it will work, altough I dont see why not...

I wonder what happens if you leave them all blank? Would that mean only ipv4 is deligated for dns?
Edit, just saw you already answered this. Assuming you put "announce router as dns..." to know this feels like a bug... sorry, Asus ipv6 support is really lacking. It hopefully gets better as people are using it and report these bugs.

If all else fail, you might need to make a custom dnsmasq.conf.add to remove the ipv6 dns line, or change it.