You are correct that only routable addresses are accepted for DNS server IPs for the router itself, but the DHCPv4 section does accept RFC1918 addresses which are then sent to clients in DHCPv4 replies.

It's good news to hear that there is plans to extend the IP validation to accept ULA addresses.

Dear TP-Link,

Please allow for my Deco BE85 to set IPv6 DNS Address to be
Link-Local Address (LLA, FE80::/64) or/and Unique Local Address (ULA, FD00::/8).

Right now Deco iOS application only allow to set IPv6 DNS Address as any Global Unicast Address (GUA, 2000::/3),
but Deco iOS application does NOT allow to set IPv6 DNS Address to be Link-Local Address (LLA, FE80::/64) or/and Unique Local Address (ULA, FD00::/8).

I'm running my own DNS server inside local network (Pi-hole),
which working perfectly fine for IPv4 (DNS address set at IPv4 DHCP settings as 192.169.1X, outside of auto assigned range), 
but I forced to disable IPv6 because I can NOT set IPv6 DNS Address for my local DNS server.

Best Regards,
Vlad
 

  @David-TP it's months since this message, yet still unsupported. Any news?

htkoca wrote

  @David-TP it's months since this message, yet still unsupported. Any news?

I actually ended up getting a router that can run the latest stable OpenWRT and it has full ULA support out of the box. However that's not why I got it.

My home internet connection which is 4G fixed wireless with a 4 port Ethernet device that does PoE to an antenna/radio on the roof connects to a local tower but from there it's RF back haul and the signal bounces through at least 4 towers before going via optic fibre cable back to the regional data centre some 200km away.

They had multiple faults on multiple towers and I had 3 hours of internet for 4 days straight and the Decos wouldn't or couldn't talk to my phone to use the internet that way via a different 4G provider but OpenWRT can do it via both USB and WiFi, and it has sooooooo many knobs you can tweak that have been hidden away or not implemented in the Deco app/routers.

The TP-Link Decos now just act as APs and were bought originally to replace an Ethernet cable that was running through the house but I didn't want to crawl under the house to re-run it and they work very well doing wireless back haul to all the kit in my comms cabinet from the living room.

As a bonus I no longer have ~0.5% of constant IPv6 packet loss and ICMPv6 packets to make IPv6 work properly as designed are also allowed through the firewall in OpenWRT, and multiple ports or port ranges can be opened for IPv6, not just single ports and DHCPv6 also can be used for LAN clients to get static assignments using their DUID, and even able to set static DHCPv4 addresses outside the DHCPv4 pool range. There is just so many things just work so well in OpenWRT that I couldn't believe it at first.

  @evilbunny that is plain sad as a be85 two unit combo is as expensive as a basic unifi setup. For devices costing up to $1.5k CAD you'd think they would have something as basic as local DNS support for ipv6 (just like how ipv4 can specify a local DNS as well)

your openwrt setup has potentially given me a use for these mesh routers. thank you

htkoca wrote

  @evilbunny that is plain sad as a be85 two unit combo is as expensive as a basic unifi setup. For devices costing up to $1.5k CAD you'd think they would have something as basic as local DNS support for ipv6 (just like how ipv4 can specify a local DNS as well)

TP-Link can't have many developers with IPv6 experience is my guess as per my last reply there is so many missing IPv6 features or managers made poor decisions, such as limiting IPv6 DNS IPs to only routable IPs, there is not a good reason I can think of why they'd do that.

There is just so many things TP-Link needs to improve such as I wrote about in this thread and another.

As for cost, the WiFi 7 chips aren't a cheap commodity chip yet, so I won't say I wasted money on the pair of BE65 Pro Deco units as they fulfil the role I bought them for.

your openwrt setup has potentially given me a use for these mesh routers. thank you

Adguard Home is a plugin for OpenWRT, and I was able to stop using Pi-Hole running as a VPS I used to run on my file server. Took a while to figure out how to transfer my config from Pi-Hole, but it seems even more powerful than pi-hole as they curate a large number of lists for all sorts of things like known DoH server hostnames.

There is also a BanIP plugin and that has all sorts of lists as well for various things too.

There is something like 10,000 plugins for stock OpenWRT, don't bother getting a router not able to run stock OpenWRT as the router I got had a customised OpenWRT version that was quite old and had lots of bugs that have been fixed since that version got released.

I got a WiFi 6 router because the WiFi 7 router only has binaries for the chip and CPU so stock OpenWRT doesn't work on it, which would mean bugs and the OpenWRT plugins wouldn't work either as the OpenWRT version is too old.

I was also able to use the Cloudflare DDNS plugin scripts to publish the current IPv4 and IPv6 address for a hostname.

I posted various things to GitHub about what can be done, started out as an IPv6 privacy repo but I've pushed a bunch of things and I should probably rename it.

https://github.com/evilbunny2008/ipv6Privacy/