Slow IP resolving

[Thomas Tanghus]

My apartment building is changing ISP, and of course the automatic update of 
the cable modem went wrong, so now I have to tether with my (Jolla) phone 
until Monday :(

Besides the already flaky modem I've had no problem with my net until now. 
Connecting to the phone works fine both for my laptop and my desktop PC, but 
for the latter resolving addresses takes forever, and connection is dropped 
all the time.

The only difference I could find is that I had dnsmasq installed on the desktop.
dnsmasq-base is installed on both, and apparently works fine on the laptop.

I tried purging dnsmasq from the desktop but to no avail - nothing changed. I 
actually had to overwrite /etc/resolv.conf with static DNS IPs (also did that 
before purging), it *seems* to work for a short while, but after that it's 
still just as slow.

Networking behind the scenes has gotten so complex that I basically have no 
idea what I'm doing :P

Any idea how/what to debug? (Not including purging NetworkManager etc.)

I am planning a reinstall as it could need some cleanup - just looking for a 
quick solution as my back, shoulders and eyes hurt from working for two days 
on the laptop...

-- 
Best regards / Med venlig hilsen

Thomas Tanghus