Where are the OpenVPN connection logs and configuration files?

If you are using the network manager plugin (network-manager-openvpn), look into /var/log/syslog

This should give you the last logs of openvpn:

$ grep VPN /var/log/syslog

Connection details are to be found in /etc/openvpn/

By default, in most distros, OpenVPN log output goes to the syslog, which is usually at /var/log/syslog

However, your config files can set the logfile location explicitly, e.g.:

log-append /var/log/openvpn.log

This works for both OpenVPN clients and servers. OpenVPN config files are usually located in /etc/openvpn and usually named *.conf. server.conf is canonical; client config filenames are usually like <client name/>.conf.

Log file location

On servers, OpenVPN is usually run as a system service, i.e., started with the --daemon option. According to the OpenVPN man page, using the --daemon [progname] option has the following effect:

Become a daemon after all initialization functions are completed. This option will cause all message and error output to be sent to the syslog file (such as /var/log/messages), except for the output of scripts and ifconfig commands, which will go to /dev/null unless otherwise redirected. The syslog redirection occurs immediately at the point that --daemon is parsed on the command line even though the daemonization point occurs later. If one of the --log options is present, it will supercede (sic) syslog redirection.

Use either of the --log file or --log-append file options if you want OpenVPN messages to be logged to a different file. The --log option causes the specified log file to be over-written each time the OpenVPN daemon starts while the --log-append option adds new entries to the log file. These options can also be set in the OpenVPN configuration file, e.g.,

log /var/log/openvpn.log

Verbosity

The --verb option can be used to set the log file verbosity from 0 (no output except for fatal errors) to 11 (for maximum debugging information). The man page specifies levels of 1 to 4 as the appropriate range for normal usage. This behaviour can be set in the OpenVPN configuration file, e.g.,

verb 3