SSH RSA host key for has changed and you have requeste

今天在209服务器上要远程登录另外一台54的服务器，结果用ssh连接提示如下错误：

[root@NHL ~]# ssh root@10.40.49.54
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    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 a host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
ed:93:ad:75:be:ff:d0:ce:60:a2:d3:d8:7d:68:a6:a1.
Please contact your system administrator.
Add correct host key in /root/.ssh/known_hosts to get rid of this message.
Offending RSA key in /root/.ssh/known_hosts:14
RSA host key for 10.40.49.54 has changed and you have requested strict checking.
Host key verification failed.

RSA host key for 10.40.49.54 has changed and you have requested strict checking.

在网上找资料，原来这是Linux重装或者openssh-server重装引起的，执行以下命令即可
ssh-keygen -R 10.40.49.5410.40.49.54换成你要连的服务器就可以了。

[root@NHL ~]# ssh-keygen -R 10.40.49.54
# Host 10.40.49.54 found: line 14 type RSA
/root/.ssh/known_hosts updated.
Original contents retained as /root/.ssh/known_hosts.old
[root@NHL ~]# ssh root@10.40.49.54
The authenticity of host '10.40.49.54 (10.40.49.54)' can't be established.
RSA key fingerprint is ed:93:ad:75:be:ff:d0:ce:60:a2:d3:d8:7d:68:a6:a1.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '10.40.49.54' (RSA) to the list of known hosts.
no such identity: /root/.ssh/id_rsa: No such file or directory
no such identity: /root/.ssh/id_dsa: No such file or directory
root@10.40.49.54's password:

我才想起来前几天我在54那台服务器上升级过ssh