release upgrade breaks internet and other things

[Tom H]

On Wed, Oct 3, 2018 at 8:45 PM Volker Wysk <post at volker-wysk.de> wrote:
> Zitat von Tom H <tomh0665 at gmail.com>:
>> On Wed, Oct 3, 2018 at 7:27 PM Volker Wysk <post at volker-wysk.de> wrote:
>>>
>>> I've done a do-release-upgrade on my 16.04 LTS system. This has broken
>>> the internet connection, and more. I get immediate "unknown host"
>>> errors when I ping to any host. When I lookup an adress in Firefox, I
>>> get a "Page not found, The connection to the server ... failed."
>>>
>>> Sorry, I don't know how to troubleshoot this connection problem.
>>>
>>> Where should I look..?
>>>
>>> Should i even look, or would it be easier to reinstall everything in a
>>> new 18.04.1 system from scratch? (This would be quite a few things.)
>>
>> Previous upgrades with network problems turned out to be dns problems.
>> /etc/resolv.conf" was a symlink pointing at the wrong file, IIRC.
>>
>> Is it a file or a symlink?
>>
>> If a symlink, to which file is it pointing?
>>
>> What are the name servers?
>
> It's a symlink to /run/resolvconf/resolv.conf. Which is EMPTY. Looks
> like we have the culprit here.
>
> It only contains this (commented out) note:
>
> # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
> #     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN

It should most likely point at "/run/systemd/resolve/resolv.conf".