SSH nem pede a senha e ja da essa mensagem...

Pessoal...estou tentando logar pelo ssh da minha estacao para o firewall....ja liberei no firewall pra conectar...mas esta dando esse esso abaixo

estou usando slack 9.1

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the RSA host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
5a:a7:47:ef:72:6b:c9:27:06:78:44:ea:d5:3c:14:bd.
Please contact your system administrator.
Add correct host key in /home/usuario/.ssh/known_hosts to get rid of this message.
Offending key in /home/usuario/.ssh/known_hosts:1
RSA host key for 192.168.1.1 has changed and you have requested strict checking.
Host key verification failed

.
Alguem pode me ajudar?