scp命令报错（IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!）

使用scp命令移动某一服务器的文件到另外的服务器时报出一下错误：

[root@bogon vm_sys1]# scp project.tar.gz root@172.31.0.90:/webdata/
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    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
00:76:4d:f0:26:a3:05:1e:d6:fd:e7:56:32:32:77:41.
Please contact your system administrator.
Add correct host key in /root/.ssh/known_hosts to get rid of this message.
Offending key in /root/.ssh/known_hosts:8
RSA host key for 172.31.0.90 has changed and you have requested strict checking.
Host key verification failed.
lost connection

仔细分析了一下大概是因为172.31.0.90的主机密钥改了，而本机使用的还是原来的公钥与其匹配，因此会出现错误。有人问不是我们使用密码么，嗯，原因是这样，一旦使用本机ssh连接过目标机，则会在~/.ssh/know_hosts文件下生成目标机的公钥，以便下次可以直接使用。所以，我们可以把该文件下172.31.0.90对应的公钥删除掉

vi ~/.ssh/know_hosts

删除掉172.31.0.90那一行。