I've just tested, and failure message that the ssh client gives if the ssh server has no keys is just simply:
Connection closed by 204.236.215.149
Also, at that point ssh-keyscan will show:
ssh-keyscan ec2-204-236-215-149.compute-1.amazonaws.com
# ec2-204-236-215-149.compute-1.amazonaws.com SSH-2.0-OpenSSH_5.3p1 Debian-3ubuntu3
Connection closed by 204.236.215.149
I've just tested, and failure message that the ssh client gives if the ssh server has no keys is just simply:
Connection closed by 204.236.215.149
Also, at that point ssh-keyscan will show: 236-215- 149.compute- 1.amazonaws. com 236-215- 149.compute- 1.amazonaws. com SSH-2.0- OpenSSH_ 5.3p1 Debian-3ubuntu3
ssh-keyscan ec2-204-
# ec2-204-
Connection closed by 204.236.215.149