Recently I’ve got a task of monitoring our site-to-site VPNs on some PIX firewalls (yeah, I know, we still use it in some locations). After a lot of researching I’ve found a working and quite decent solution for now. Monitoring specific syslog IDs for VPN disconnections looks like the way to go.
I’m going to start off with PIX and will add the ASA config when I lab it up.
Note: You need not setup logging lists if you are already monitoring error level logs and above because the log message ID that we explicitly want to log for our VPN monitoring is a warning level log. Hence my logging list has a separate critical (level 2) logging as the VPN monitoring isn’t covered under that level.