Linux下ssh單向免密登陸/互免密登陸

//單向免密登陸
//A端
# cat /etc/redhat-release 
CentOS Linux release 7.6.1810 (Core)
# ssh-keygen -t rsa		//生成公鑰與私鑰(運行該命令後 三次 回車)
# ssh-copy-id [B端ip]	//需要輸入B端密碼
# ssh [B端ip]		//免密登錄成功

//B端
# cat /etc/redhat-release 
CentOS release 6.8 (Final)

//互免密登陸
//注意：在本示例中使用的用戶是root,如果使用其他用戶時，A端與B端要存在相同名稱的用戶

//系統 CentOS Linux release 7.7.1908 (Core)
//A端	ip：192.168.56.10
# ssh-keygen -t rsa -P ''
# chmod 600 ~/.ssh/authorized_keys	//一般.ssh目錄下存在authorized_keys文件,如不存在則手動創建並修改權限爲600
# cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
# scp ~/.ssh/id_rsa.pub root@[B端ip]:~	//把id_rsa.pub拷貝給B端,複製粘貼id_rsa.pub內容到B端也可
# cat ~/id_rsa.pub >> ~/.ssh/authorized_keys	//追加到authorized_keys中

//系統 CentOS Linux release 7.7.1908 (Core)
//B端	ip：192.168.56.20
# ssh-keygen -t rsa -P ''
# chmod 600 ~/.ssh/authorized_keys
# cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
# scp ~/.ssh/id_rsa.pub root@[A端ip]:~	//把id_rsa.pub拷貝給A端,複製粘貼id_rsa.pub內容到B端也可
# cat ~/id_rsa.pub >> ~/.ssh/authorized_keys	//追加到authorized_keys中

//A端測試
# ssh [B端ip]
//B端測試
# ssh [A端ip]