Hi @anon42188109,
Looking back over this thread I have found that sdrbox1 is a pc running Ubuntu
I believe that the testing of the dig commands is being done from a lan pc with IPFire either in place or out of loop.
Looking back over the thread it seems to be more related to problems in having apt-get to work properly.
@sboyce should confirm if that is still the problem being experienced.
If yes then this could be related to a bug that Ubuntu and Debian have (or have had, I don’t know if it has been fixed in later releases) where if an ipv6 communication occurs from the dns system then Ubuntu will only try to update via ipv6 even if an ipv4 address is provided.
See thread https://community.ipfire.org/t/dns-returning-ipv6-addresses-can-cause-breakage/5595
I ran a test with Ubuntu 20.04.3 which is an LTS release and had no problems with running apt-get update or upgrade. From the thread it looks @sboyce is on Ubuntu Impish which is 21.10, an interim release.
Later on I will test out installing Ubuntu Impish on a vm and see if I have a similar problem or not. I will also test it with aptitude update which is what was used by @sboyce but as far as I am aware aptitude just is a higher level operation of apt-get so the same final program is run.