Regression: WiFi connection reconnects, but dead, after waking from standby

[dronus]

Bug introduced somewhere between Ubuntu 14.04.3 and 16.04.1

If my Thinkpad T420s awakes from standby, very often the last connected WiFi network is reconnected immediately, but the connection is dysfunctional.

ifconfig shows a valid connection with an IPv4 address assigned for the wlp3s0 interface.

But there is no traffic, no success on DNS queries on the connection.

If I reconnect by clicking the connection in the nm-applet menu, all is fine again.

[Benjamin Schmid (benbuntu)]

Same issue here after upgrading from xenial 16.04 to yakkety 16.10: After standby I can ping valid IP addresses, but DNS fails. Restarting the network manager via ` sudo /etc/init.d/network-manager restart` does mend the situation.

In this SO post https://askubuntu.com/q/837575/94728 people report the same issue. A answer proposes to disable dnsmasq in network manager by commenting out `dns=dnsmasq` in `/etc/NetworkManager/NetworkManager.conf`as workaround.

[Launchpad Janitor (janitor)]

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

[Noam Mor (noam-mor)]

Affects me too, on Dell XPS 9550, after upgrade from 16.04 to 16.10. Commenting out the `dns=dnsmasq` solved the issue for me.

[Kseniya Blashchuk (ksyblast)]

Same for me on Dell XPS 9550 with 16.04