ssh用法及命令

1）ssh用于连接另一个客户端
ssh 远程主机用户@远程主机ip
[[email protected] ~]# ssh [email protected]
The authenticity of host ‘172.25.0.11 (172.25.0.11)’ can’t be established.
ECDSA key fingerprint is eb:24:0e:07:96:26:b1:04:c2:37:0c:78:2d:bc:b0:08.
Are you sure you want to continue connecting (yes/no)? yes ##连接陌生主机时需要建立认证关系
Warning: Permanently added ‘172.25.0.11’ (ECDSA) to the list of known hosts.
[email protected]’s password: ##远程用户密码
Last login: Mon Oct 3 03:13:47 2016
[[email protected] ~]# ##登陆成功

2）sshkey加密
生成公钥私钥

id_rsa ##私钥，就是钥匙
id_rsa.pub ##公钥，就是锁

使用公钥(锁)将用户锁上

发送私钥给指定用户

3）提升openssh的安全级别

vim /etc/hosts.deny
sshd:ALL ##拒绝所有人链接sshd服务

vim /etc/motd ##显示登陆后字符