Coding an example SFTP client for a friend (using WinSCP) today, I realised I needed the 2048-bit RSA fingerprint for my server.
You see the fingerprint the first time you connect to a new server and, normally, you will save this locally so that you can verify the identity of the server next time that you connect to it. A changed fingerprint is evidence of a possible “man in the middle” attack.
I found a simple way to find out the RSA finger print of a server from the command line using nmap
nmap [SERVERNAME] --script ssh-hostkey