what is the differnce between the normal ssh server and openssh?
 

what is the differnce between the normal ssh server and openssh?

Which one do you mean? Can you provide a specific name or URL? The OpenSSH server is the normal one. It's in any distro you'd care to install, it's also got an overwhelmingly large portion of the install base for all other devices.

However, any of them will be using the SSH 2 protocol as defined in the RFCs.

"Original" ssh server and openssh:
https://www.openssh.com/portable.html

Virtually every ssh server that you're likely to encounter (unless you're talking to a Windows box) will be OpenSSH.

And in any case, the source-code that you are talking to will basically be the same. So, it is most likely to be "a difference that makes no difference."

Therefore: "why," may I ask, "do you ask?"