How can I access debug info for failing VPN connection via Network Manager? [duplicate]

I have a VPN connection set up via the Network Manager. Today it failed because I forgot make the key files accessible, once I made them accessible, it worked. Yay!

But, what if I hadn't remembered? It would have been helpful to be able to see the actual debug/info/warn/error messages.

Where are these logs located? Or, if they are not stored, how can I attempt to the connection from the command line (and see the output there)?


This applies here as well:

Log is written to /var/log/syslog.
Open a terminal and write tail -f /var/log/syslog.