Comparing NRPE and SSH
Both SSH and NRPE are used to perform checks on remote machines. They can be set up to perform the same tasks. There are some differences and each solution is better in certain conditions.
SSH-based checks are 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 there's usually no changes in firewall configurations 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, Nagios server can run any command on any of the machines that it can access. One way of limiting this problem is to set up a restricted shell...
