I have an ESX box which I have loaded with two Ubuntu Server machines.

During setup, I chose no additional packages to install as I just wanted a lightweight machine for testing.

The first thing I did was change the root password via sudo passwd

After ESX got on my nerves through lag, I decided to install OpenSSH via apt-get install openssh-server.

It did it's business, and I then opened putty and could connect in to both machines fine. The first time it connected, it asked me to add the ssh key as obviously it did not know it.

Anyway, the second server is working flawlessly, but, the first seems to be giving me trouble.

I was in the middle of typing a sentence when it kicked me off for no reason and when I tried to reconnect, putty gave me a warning that the ssh key had changed and it is potentially dangerous. I attempted to log in anyway and it did not work, just the standard access denied message.

Using the second machine, I SSHed in to the first machine and it worked straight away, I then killed the SSH sessions (and possibly SSH server), I then reconnected via putty and I again received the security warning message, but, it allowed me to log on fine.

... I thought "glitch" and nothing more of it, but, it just happened again!

I really do not understand this and was hoping someone here can help?