I'm a developer with about 20 different clients running our server application. I access each of the clients' servers remotely through VPN to provide support, updates, etc.

Is there any tool available that I can set up locally that will connect through each of the VPNs automatically to allow me to monitor?

The idea sounds very far fetched to me as the VPN software varies a good bit but maybe someone's had to do something similar before?

It's been a few years since I last used Nagios but I think it'd be quite cool to have that set up pointing at each of the remote servers through VPN somehow.