Is it possible to monitor an IPSec tunnel?

I am wondering if this is possible within nagios? If so could somebody lead me in the right direction as to what strings I input in what config file?

We have a *nix box that has IPSec on it with a secure tunnel going to another company, I would like to know when that service stops or the tunnel “breaks”. Thanks in advance

Jordan

You can use NRPE to check for a specific service running.

nagios.sourceforge.net/docs/nrpe/NRPE.pdf

what if you monitor something on the distant end of the tunnel on the private IP. That way if the tunnel goes down you lose the private IP and lose the monitor. Could be a basic service on the server you are connection to. Not sure if that will work but it is a thought anyhow.