IPv6 DNS (over TLS) servers not used

[joeyboon]

Hi everyone,

I switched ISP and now connect (on version 21.7.1) through PPPoE and automatically get a static IPv4 address assigned on the WAN interface and as far as I understand by design don't get an IPv6 address on the WAN interface. Because IPv6 is handled through the PPPoE-tunnel via DHVPv6 Prefix Delegation.

I assign every other internal VLAN a /64 via the Track interface setting and track the WAN interface. Depending on if I enable the "Request only an IPv6 prefix" option on the WAN interface, the WAN interface does get a link local address.

This all seems to works like charm. Clients on the LAN and other VLAN's get a IPv6 address, the interface itself (LAN etc) gets an IPv6 address. Clients register the interface (IPv4 and IPv6) as DNS server. Life is good.

This does however create a problem for unbound and upstream DNS, since the WAN interface is selected as the outgoing network interface, IPv6 Nameservers can't be used (since WAN does not have an IPv6 address). If I try to enable them the unbound log's get flooded with this message:

error: outgoing tcp: bind: Can't assign requested address

I found these posts already, all related to my problem:

How to use own IPv6 DNS server with a track LAN interface?
https://forum.opnsense.org/index.php?topic=19144.0

DNS over TLS with ipv6 forward-addresses - can't get it working
https://forum.opnsense.org/index.php?topic=19851.0;prev_next=prev#new

DNS Servers with ipv6 addresses not usable with LL ipv6 gateway addresses
https://forum.opnsense.org/index.php?topic=19746.0

They all offer insights, but I can't seem to get it working. Hopefully someone will be able to help me out  .

[joeyboon]

I think I figured it out! . By disabling WAN as outgoing interface in Unbound and enabling all the others I now see IPv6 DNS over TLS servers being used! IPv4 also still works!

[Napsterbater]

So for your first post, was "All" not set for "Outgoing Network Interfaces"? All is the default and should work fine.

[joeyboon]

I must have changed it to WAN only in the past (don't now why). Was frustrated with this for days . In the end the problem is  usally between the keyboard and the chair