DNS stops working when disconnecting PPTP VPN on desktop

[Will Cooke]

On Cosmic I was testing some VPN setups. I created a PPTP VPN connection to my server.
Everything connected and worked as it should.

When I disconnect the VPN, DNS resolution stops working.

Looking at "systemd-resolve --status" shows that the correct DNS server is listed for the interface when the connection is torn down, and I can ping it. Doing a nslookup setting the server to the IP address shown in --status shows that DNS resolution is working correctly.

resolv.conf says nameserver 127.0.0.53

Restart resolved makes things work again.
(Also, restarting Network Manager makes it work again.)

Trying to ping a hostname from the cli when in the broken state yields zero output from resolved logs when in debug mode. Almost like it's not even hitting resolved, so this bug could very well be somewhere else.

I've checked, and I can ping 127.0.0.1 and the default routes look OK, although there is a route to the VPN server left over.

I'm all out of ideas. Any ideas?

[Emmanuel DA MOTA (vilain-mamuth)]

is this a duplicate of https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1778946 ?

[Will Cooke (willcooke)]

Yeah, I think so. Thanks.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Chris (cnizzardini)]

This is happening for me as well.

Distributor ID: Ubuntu
Description: Ubuntu 18.04.3 LTS
Release: 18.04
Codename: bionic