Monitoring and Alerting When IPSEC Tunnel is Down or Fails

[bshack]

Before I embark on a long and possibly fruitless journey I figured it would be worth asking if anyone has already come up with a solution to the above question.  We want to monitor the status of the IPSEC tunnels on our PFSense box and issue a alert if a tunnel goes down.  I am wondering what options were available for that.  I am hoping someone can just say "hey go use this method" and away we go.  If not, then this will be an even more exciting journey into the unknown.

Thanks!

[cmb]

The general purpose network availability monitoring system you use to monitor servers, switches, routers, firewalls, etc. A ping to the remote end would suffice.