什么是ssh
管理員可以通過遠程登陸的方式，對通過網相連的分散于各處的多臺主機進行管理操作。
管理員可以對遠程主機進行如下操作：
遺憾的事情是：這些操作不安全！
使用純文本口令，并用明文發送
- 信息可能會被截取，口令可能會被檢索
- 未經授權的人員使用截取的口令登陸系統而對系統造成危害
在日常操作練習時，用ssh登錄其他主機時，可能會每次都需要輸入登錄密碼，哪怕用scp復制東西也需要。
為了更方便快捷的切換主機，ssh免密通信不失為更好的選擇；
用ssh-keygen生成密鑰，默認保存在本地的/root/.ssh/id_rsa
然后在用ssh-copy-id分發至目標主機之上；登錄用戶@主機名或IP地址
注意：
1.最好是用主機名，在/etc/hosts文件中寫入主機名和對應的IP地址；
2.免密通信需要雙方相互認證，所以也需要在目標主機對本機做一次相同的操作；
[root@www ~]# ssh-keygen -t rsa -P ''
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
/root/.ssh/id_rsa already exists.
Overwrite (y/n)?
[root@www ~]#ssh-copy-id -i .ssh/id_rsa.pub root@172.16.75.1
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: ".ssh/id_rsa.pub"
The authenticity of host '172.16.75.1 (172.16.75.1)' can't be established.
ECDSA key fingerprint is SHA256:YXhbTS9MfK2IQC4gtOW4RL8voHvFqC1cAAMJXuF3Wec.
ECDSA key fingerprint is MD5:2c:c0:94:e8:3a:e4:74:88:c0:d8:e0:01:20:81:1d:8e.
Are you sure you want to continue connecting (yes/no)? yes
/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@172.16.75.1's password:
Number of key(s) added: 1
Now try logging into the machine, with: "ssh 'root@172.16.75.1'"
and check to make sure that only the key(s) you wanted were added.
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持腳本之家。
