关于ssh 的补充，平时不注意的地方 在known_hosts中， 同一个主机的ssh_host_key, 域名和ip访问，追加一条记录到know_hosts中

[root@blog ~ 23:44:49]$cat ~/.ssh/known_hosts
192.168.85.253 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBDCSZVXIgOQwQDZ9iNLtuB7bi//IOYxYe/3vo68Bpn+5lOtn9NvpIMwjmGXb94MRlPPWBzVqZPr4K+Y9/X561Co=
172.16.1.242 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBMe+WuFNGloFWBtqjvDxVqGWyA1Rd1+zo1mXMQWJMA4i+ZSderULMKYxuhAlfUO+WrcxWFuIXVWJAGrG85DUq74=
192.168.85.251 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBF595fYtdngg17R329Av/aqmBgn0iL8EK3kJWdC7MRBM8p1X8UAmUx5ueoXArwjWd5LlEhtS5D7cZC5PeSvx0fM=
192.168.85.252 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBDCSZVXIgOQwQDZ9iNLtuB7bi//IOYxYe/3vo68Bpn+5lOtn9NvpIMwjmGXb94MRlPPWBzVqZPr4K+Y9/X561Co=
bogon.cc.cc ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBDCSZVXIgOQwQDZ9iNLtuB7bi//IOYxYe/3vo68Bpn+5lOtn9NvpIMwjmGXb94MRlPPWBzVqZPr4K+Y9/X561Co=
blog.cc.cc ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBDCSZVXIgOQwQDZ9iNLtuB7bi//IOYxYe/3vo68Bpn+5lOtn9NvpIMwjmGXb94MRlPPWBzVqZPr4K+Y9/X561Co=
[root@blog ~ 23:45:15]$> ~/.ssh/known_hosts
[root@blog ~ 23:45:36]$ssh-copy-id -o StrictHostKeyChecking=no 192.168.85.252
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
root@192.168.85.252's password:
Permission denied, please try again.
root@192.168.85.252's password:

Number of key(s) added: 1

Now try logging into the machine, with: "ssh -o 'StrictHostKeyChecking=no' '192.168.85.252'"
and check to make sure that only the key(s) you wanted were added.

[root@blog ~ 23:46:32]$ssh -o StrictHostKeyChecking=no 192.168.85.252
Last failed login: Fri Apr 3 11:46:28 EDT 2020 from blog.cc.cc on ssh:notty
There was 1 failed login attempt since the last successful login.
Last login: Fri Apr 3 11:44:48 2020 from blog.cc.cc
Your login is logging, please xiaoxing operation
[root@blog ~ 23:46:43]$exit
logout
Connection to 192.168.85.252 closed.
[root@blog ~ 23:46:44]$ssh -o StrictHostKeyChecking=no blog.cc.cc
Warning: Permanently added 'blog.cc.cc' (ECDSA) to the list of known hosts.
Last login: Fri Apr 3 11:46:42 2020 from blog.cc.cc
Your login is logging, please xiaoxing operation
[root@blog ~ 23:46:52]$