Comment 1 for bug 410968

You can change the default interface that gets used when parameter -i isn't present from the configuration file /etc/vnstat.conf by changing the "Interface" setting. However, it seems that 1.6-1 doesn't install any configuration file although such existed in the original upstream install script. That configuration file can be later created with "sudo vnstat --showconfig >/etc/vnstat.conf".

The current upstream version (1.8) adds also the current and previous months to the summary output compared to version 1.6.