My last post detailed how to install and configure Fail2Ban on a Ubiquiti EdgeRouter to thwart brute force attacks against an OpenVPN server. Unfortunately, programs installed on EdgeRouters do not persist through upgrades because new images overwrite the filesystem. However, using a trick outlined here, we can set up the router to automatically install Fail2Ban and restore the settings.
Tonight, I noticed numerous attempts from a variety of sources to log in to my OpenVPN server that I run on my EdgeRouter (ER-X-SFP) at home. Unfortunately EdgeRouter doesn’t support any sort of blacklisting for OpenVPN natively, but it does allow the installation of Debian packages.
After playing a bit with Fail2Ban configuration, I’ve configured my router to block these repeated attempts automatically.