Upgrade from 20.04 to 22.04 and SOME domain names won't resolve

Haxsaw

3/29/24, 8:42 PM

I've looked through the questions and haven't seen anything like this odd problem.

I just finished a project and thought I'd finally address the reminders I kept getting to upgrade from 20.04 to 22.04. The upgrade ran without incident, but upon reboot a raft of problems became apparent. But the worst one is that SOME domain names won't resolve. It's really weird: I can reach google.com, reddit.com, ubuntuforums.org, python.org...lots of places. But so far my machine refuses to be able to find:

github.com
api.pcloud.com
duckduckgo.com

...and I'm sure there are more to be discovered. The problem isn't my internal network or router-- I can reach all of these from other boxes on my same net. It also only started happening right after the upgrade to 22.04. I've done several reboots (for other reasons) and the behavior remains. The problem exhibits itself in browsers, with traceroute, and with ping, which gives messages like:

$ ping github.com
ping: github.com: No address associated with hostname

BTW, this is not tied to the recent outage at github.com: as I said, I can reach all of these destinations from other machines in my network, so I know it isn't that.

I tried looking for firewall rules with but ufw says it's inactive.

I don't even know where to begin to look about such a weird problem. I'm happy to research other doc if someone could give me some clues/pointers of where to look, but right now I'm kind of at a loss. Since this is my dev box getting to github is kinda a big deal.

Thanks for any help.

0 + 2

upgrade

networking

dns

22.04

Haxsaw

3/31/24, 2:15 PM

OK, just a new detail to add: prior to the upgrade, I had VirtualBox installed, so on a hunch I started it and fired up a Linux VM I had laying around. From inside the VM, I was able to ping github.com just fine, but within the host Linux system I still get the 'No address' error mentioned in the original post. This smacks of a configuration issue, as I can clearly get to github.com from the same physical machine.

David

4/1/24, 1:54 PM

Please use the edit command and add any new info to the question. Do not make them a comment. Comments are for anyone helping you to ask for more info.

Elon Musk

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