Both SSH and NRPE are used to perform checks on remote machines. They can be set up to perform the same tasks; however, there are some differences and each solution is better in certain conditions. Depending on what the critical issues are for your network, the choice is usually to either use SSH or NRPE to perform the checks on other machines.

The first is easier to set up from a network and administrative perspective. All that is needed is to put a set of plugins on the machine, create a public key-based authentication, and you are all set to go! The main advantage of this method is that it uses the existing network protocol, which is usually running and enabled on all Unix-based machines. This way, it is not necessary to configure firewalls to pass traffic related to the Nagios checks if the server that Nagios is running on can already connect to other hosts using the SSH protocol.

Security and performance are the trade-offs. As SSH is a generic protocol, the Nagios...