SSH weirdness

Since this is my first time encounter this type of SSH error, so it was weird.

abc123 % ssh def456
Secure connection to def456 refused; reverting to insecure method.
Using rsh. WARNING: Connection will not be encrypted.
Password:

I was like, wtf?

As usual, I asked Google and got some insights. Basically those error generated if you're trying to ssh to a Windows NT(?) or maybe the ssh daemon on the remote server is not running.

In my case, I found out that def456 was pointing to a different IP and my intelligent guess would be that IP belongs to a Winblows machine.