I wrote a tutorial on the new certificate handling in 0.4.1 and how to setup various forms of certificate based authentication. ''NRPE is a common easy to use option for monitoring remote machines from Nagios or Icinga. Unfortunately NRPE, with out of the box setup, is not what I would consider secure. This tutorial looks at how you can secure your NRPE traffic by using NSClient++ both as a client and server (yes it runs on Linux as well) in conjunction with SSL certificates to provide certificate based authentication.'' You can find the full post here: http://blog.medin.name/2012/12/02/securing-nrpe-with-certificate-based-authentication/ // Michael Medin