Ssl keys - novice question

Knowing very little about ssl keys, I have a novice question about how they work, in my case with nrpe.

I install nrpe on a Windows client, then blindly copy the ssl key from an existing client to the matching location on the new client. And magic, the check_nrpe on our Solaris Nagios 3 server can then do checks of the new client.

But there must be cooperating processes on the client and the server that do the authentication handshake, right?

In the nrpe client install, I don’t tell nrpe where the ssl key is located, so I figure it’s some other process doing the work.

On the Solaris Nagios server, there must be a matching key showing what to send to or expect from the client, right? But I don’t know where that key is located or who’s doing the work on the server side.

Thanks for pointing me in the right direction on this…Lyle