Diagnose DNS problem

[Paul Smith]

On Sun, 2022-10-02 at 16:32 +0200, Ralf Mardorf via ubuntu-users wrote:
> For testing purpose I usually run
>   
>   dig a.domain.org

dig is great but IME it's not always installed on all systems, and if
you don't have DNS it can be hard to install new software :).

I believe that the host(1) command does the important stuff (for
troubleshooting local DNS issues) that dig does, and it's always
installed as part of the default system.  So that's my preference.

> I'm interested in suggestions, too.

As mentioned to Colin there are so many ways (far TOO many ways) to
configure DNS these days so the first thing is always to determine
which one you're using.

The way to do that is look at /etc/resolv.conf: even with all the other
changes, that's still how all software on your system determines how to
perform DNS lookups so it's the starting point.

Once you know what facility you're using, you can begin to troubleshoot
it.