One of our bank customers has a vendor that monitors the status of one of their servers remotely through a VPN connection.  In the past few days, something has happened to where they call saying that they are detecting the server is down or unreachable.  The bank had not noticed any problems in their ability to provide service to their customers as they usually get calls when something isn’t working right.

The vendor began troubleshooting network connectivity and determined later that there didn’t seem to be a network problem, but their network monitoring software was still indicating the server was down.  They later said that the problem had been traced to an “application” problem.  Rebooting the server brought the connectivity back up with their monitoring software.  The application running on the bank server had stopped responding and blocked incoming requests from the vendor’s monitoring software. This is an example of network monitoring software only being as good as the application on the other end.