修改/etc/hosts的对应关系后，无法通过ssh直接访问。需要从 known_hosts 文件中删除所属于 hostname 的密钥。

[root@test etc]# cat hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

192.168.244.136         test
192.168.244.137         test1
192.168.244.138         test2

修改对应关系后ssh则显示以下提示。

[root@test etc]# ssh test1
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@       WARNING: POSSIBLE DNS SPOOFING DETECTED!          @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
The RSA host key for test1 has changed,
and the key for the corresponding IP address 192.168.244.137
is unchanged. This could either mean that
DNS SPOOFING is happening or the IP address for the host
and its host key have changed at the same time.
Offending key for IP in /root/.ssh/known_hosts:3
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    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
ae:ec:e2:92:18:fb:28:8e:c0:8d:ba:b1:2d:c4:3e:0f.
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:1
RSA host key for test1 has changed and you have requested strict checking.
Host key verification failed.

从 known_hosts 文件中删除所属于 hostname 的密钥。

ssh-keygen -R test #test输入需要重链的地址

在尝试ssh链接，已成功

[root@test ~]# ssh test1
The authenticity of host 'test1 (192.168.244.137)' can't be established.
RSA key fingerprint is ae:ec:e2:92:18:fb:28:8e:c0:8d:ba:b1:2d:c4:3e:0f.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'test1,192.168.244.137' (RSA) to the list of known hosts.
root@test1's password:
Last login: Mon Apr 19 20:36:39 2021 from 192.168.244.136

##或者你可以选择更加直接的操作

rm -rf /root/.ssh/*