unit9.openssh-server 1.openssh-server 功能：让远程主机可以通过网络访问sshd服务，开始一个安全shell ####2.客户端连接方式#### ssh 远程主机用户@远程主机ip [root@desktop0 ~]# ssh root@172.25.0.11 The authenticity of host '172.25.0.11 (172.25.0.11)' can't beestablished. 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. root@172.25.0.11's password: ##远程用户密码 Last login: Mon Oct 3 03:13:472016 [root@server0 ~]# ##登陆成功 ssh 远程主机用户@远程主机ip -X ##调用远程主机图形工具 ssh 远程主机用户@远程主机ip command ##直接在远程主机运行某条命令 ####3.sshkey加密#### 1.生成公钥私钥 [root@server0 ~]# ssh-keygen ##生成公钥私钥工具 Generating public/private rsa key pair. Enter file in which to save the key (/root/.ssh/id_rsa):[enter] ##加密字符保存文件（建议用默认） Created directory '/root/.ssh'. Enter passphrase (empty for no passphrase): [enter] ##密钥密码，必须>4个字符 Enter same passphrase again: [enter] ##确认密码 Your identification has been saved in /root/.ssh/id_rsa. Your public key has been saved in /root/.ssh/id_rsa.pub. The key fingerprint is: ab:3c:73:2e:c8:0b:75:c8:39:3a:46:a2:22:34:84:81 root@server0.example.com The key's randomart image is: +--[ RSA 2048]----+ |o | |E. | |.. | |. . o | |.o. * . S | |oo.o o . | |+ =. . . | |o. oo.+.. | | ..o*. | +-----------------+ [root@server0 ~]# ls /root/.ssh/ id_rsa id_rsa.pub id_rsa ##私钥，就是钥匙 id_rsa.pub ##公钥，就是锁 2.添加key认证方式 [root@server0 ~]# ssh-copy-id -i /root/.ssh/id_rsa.pub root@172.25.0.11 ssh-copy-id ##添加key认证方式的工具 -i ##指定加密key文件 /root/.ssh/id_rsa.pub ##加密key root ##加密用户为root 172.25.0.11 ##被加密主机ip 3.分发钥匙给client主机 [root@server0 ~]# scp /root/.ssh/id_rsa root@172.25.0.10:/root/.ssh/ 4.测试 [root@desktop0 ~]# ssh root@172.25.0.11 ##通过id_rsa直接连接不需要输入用户密码 Last login: Mon Oct 3 03:58:10 2016 from172.25.0.250 [root@server0 ~]# ####4.提升openssh的安全级别#### 1.openssh-server配置文件 /etc/ssh/sshd_config 78 PasswordAuthentication yes|no ##是否开启用户密码认证，yes为支持no为关闭 48 PermitRootLogin yes|no ##是否允许超级用户登陆 49 AllowUsers student westos ##用户白名单，只有在名单中出现的用户可以使用sshd建立shell 50 DenyUsers westos ##用户黑名单
