Where are network manager logs? (16.04)

Question

I have new Ubuntu and I want to debug some errors in network settings.

I cannot find log for NetworkManager.

/var/log/syslog and /var/log/daemon.log - what people recommend on this stack exchange in other questions - are both empty.

Python script from this page - https://wiki.ubuntu.com/DebuggingNetworkManager - doesn't exist anymore.

sudo service network-manager status displays a few lines of the log, but not all.

Answer 1

journalctl does the trick:

journalctl -u NetworkManager.service

-u, --unit=UNIT|PATTERN Show messages for the specified systemd unit UNIT (such as a service unit), or for any of the units matched by PATTERN. [...]

Answer 2

You can also try this one. You'll see some Network Manager state changes with this one.

sudo journalctl -fu NetworkManager

e.g.,

Mar 15 09:06:37 macbookair NetworkManager[1098]: <info>  [xxx] keyfile: add connection in-memory (xxx,"tun0")
Mar 15 09:06:37 macbookair NetworkManager[1098]: <info>  [xxx] device (tun0): state change: unavailable -> disconnected (reason 'connection-assumed', sys-iface-state: 'external')
Mar 15 09:06:37 macbookair NetworkManager[1098]: <info>  [xxx] device (tun0): Activation: starting connection 'tun0' (xxx)

-f, --follow Show only the most recent journal entries, and continuously print new entries as they are appended to the journal.