DNS64 prefix not being synthesized for some IPv4-only domains

[awatson2012]

Prerequisites

• I have checked the Wiki and Discussions and found no answer

• I have searched other issues and found no duplicates

• I want to report a bug and not ask a question or ask for help

• I have set up AdGuard Home correctly and configured clients to use it. (Use the Discussions for help with installing and configuring clients.)

Platform (OS and CPU architecture)

FreeBSD, AMD64 (aka x86_64)

Installation

Other (please mention in the description)

Setup

On a router, DHCP is handled by the router

AdGuard Home version

107.55

Action

Enabled DNS64 on AdGuard Home and specified the default DNS64 prefix as follows:
use_dns64: true
dns64_prefixes:
- 64:ff9b::/96

My AdGuard Home server is running on an OPNsense router and is using quad9 DNScrypt as its upstream resolver.

Expected result

IPv4-only domains should include the synthesized DNS64 address.

Actual result

Some IPv4-only domains included the DNS64 address in the response (in this case completion.amazon.com). Others did not include the DNS64 prefix (www.reddit.com). It appears that the issue occurs when the requested domain is an alias to another name.

Additional information and/or screenshots

No response

[github-actions]

Potential duplicates:

• [Specific DNS for some clients seems to be not working #7422] Specific DNS for some clients seems to be not working (60.99%)

[L2jLiga]

Hello @awatson2012, I've recently faced with same issue and it prevents me from adding DHCP option 108.

I've created issue in dnsproxy: AdguardTeam/dnsproxy#438
and PR fixing it as well: AdguardTeam/dnsproxy#439

after that I've build latest version of AdGuardHome with my changes:

git clone https://github.com/AdguardTeam/AdGuardHome.git
cd AdGuardHome
make
go mod edit -replace="github.com/AdguardTeam/dnsproxy@v0.75.0=github.com/L2jLiga/dnsproxy@dns64-fix"
go mod tidy
make
systemctl stop AdGuardHome
mv /opt/AdGuardHome/AdGuardHome /opt/AdGuardHome/AdGuardHome.bak
cp ./AdGuardHome /opt/AdGuardHome/AdGuardHome

[L2jLiga]

As of now I don't have any troubles with my IPv6-mostly network - DNS64 works as expected, NAT64 via Jool also =)