SSH简介：

SSH的简单介绍
1、安全外壳协议；
2、建立在应用层上的软件；
3、跨平台；
4、安全；

1.1 在Centos安装SSH服务（默认安装的）

要启动服务，然后设置开机运行chkconfig sshd on

1.2客户端的SSH工具：

典型的CS交互模式，有多种SSH软件连接。
在安装sever时候已经把client安装过了。

1.3使用SSH命令链接服务——命令行

macOS下使用teminal进行连接SSH：
命令非常的简单：ssh [username]@[domain_name] Last login: Mon Apr 16 19:27:21 on ttys001 zhangyunchendeMacBook-Pro:~ zhangyunchen$ ssh usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec] [-D [bind_address:]port] [-E log_file] [-e escape_char] [-F configfile] [-I pkcs11] [-i identity_file] [-J [user@]host[:port]] [-L address] [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port] [-Q query_option] [-R address] [-S ctl_path] [-W host:port] [-w local_tun[:remote_tun]] [user@]hostname [command] zhangyunchendeMacBook-Pro:~ zhangyunchen$ zhangyunchendeMacBook-Pro:~ zhangyunchen$ zhangyunchendeMacBook-Pro:~ zhangyunchen$ zhangyunchendeMacBook-Pro:~ zhangyunchen$ ssh root@192.168.0.114 The authenticity of host '192.168.0.114 (192.168.0.114)' can't be established. ECDSA key fingerprint is SHA256:VoLf/WSoie6PfXjWGPGmkHnfTeiUDHMCizH+hj+il+Q. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added '192.168.0.114' (ECDSA) to the list of known hosts. root@192.168.0.114's password: Last login: Mon Apr 16 07:33:36 2018 from 192.168.0.155 [root@localhost ~]# [root@localhost ~]# [root@localhost ~]# [root@localhost ~]# exit 登出 Connection to 192.168.0.114 closed. zhangyunchendeMacBook-Pro:~ zhangyunchen$ exit logout Saving session... ...copying shared history... ...saving history...truncating history files... ...completed.

1.4 SSH config讲解

使用config是可以用来批量管理多个SSH，典型的运维要学会的技能。一般的config存放在~/.ssh/config config的配置语法 语法关键词：
HostName;
Port;
User;
IdentityFile;秘钥文件路径 这个SSH config我感觉非常的像JSON文件的格式：host “centos” Hostname 192.168.0.114 User root Port 22 IdentityFile ~/.ssh/id_rsa.pub IndentitiesOnly yes 具体操作： Last login: Mon Apr 16 19:36:20 on ttys001 zhangyunchendeMacBook-Pro:~ zhangyunchen$ ssh root@192.168.0.105 ^Z [1]+ Stopped ssh root@192.168.0.105 zhangyunchendeMacBook-Pro:~ zhangyunchen$ ssh root@192.168.0.114 root@192.168.0.114's password: Last login: Mon Apr 16 07:37:39 2018 from 192.168.0.155 [root@localhost ~]# [root@localhost ~]# [root@localhost ~]# [root@localhost ~]# [root@localhost ~]# exit 登出 Connection to 192.168.0.114 closed. zhangyunchendeMacBook-Pro:~ zhangyunchen$ cd ~/.ssh zhangyunchendeMacBook-Pro:.ssh zhangyunchen$ ls known_hosts zhangyunchendeMacBook-Pro:.ssh zhangyunchen$ touch config zhangyunchendeMacBook-Pro:.ssh zhangyunchen$ ;s -bash: syntax error near unexpected token `;' zhangyunchendeMacBook-Pro:.ssh zhangyunchen$ ls config known_hosts zhangyunchendeMacBook-Pro:.ssh zhangyunchen$ vim config zhangyunchendeMacBook-Pro:.ssh zhangyunchen$ ssh Centos root@192.168.0.114's password: Last login: Mon Apr 16 07:45:40 2018 from 192.168.0.155 [root@localhost ~]# vim config [1]+ 已停止 vim config [root@localhost ~]# vim ~/.ssh/config [2]+ 已停止 vim ~/.ssh/config [root@localhost ~]# cd ~/.ssh -bash: cd: /root/.ssh: 没有那个文件或目录 [root@localhost ~]# cd ~/.ssh/ -bash: cd: /root/.ssh/: 没有那个文件或目录 [root@localhost ~]# exit 登出 有停止的任务。 [root@localhost ~]# exit 登出 Vim: Caught deadly signal TERM Vim: Finished. Vim: Caught deadly signal TERM Vim: Finished. Connection to 192.168.0.114 closed. zhangyunchendeMacBook-Pro:.ssh zhangyunchen$ vim config [2]+ Stopped vim config zhangyunchendeMacBook-Pro:.ssh zhangyunchen$ zhangyunchendeMacBook-Pro:.ssh zhangyunchen$ zhangyunchendeMacBook-Pro:.ssh zhangyunchen$ zhangyunchendeMacBook-Pro:.ssh zhangyunchen$ cat config > host "Centos" HostName 192.168.0.114 User root Port 22 zhangyunchendeMacBook-Pro:.ssh zhangyunchen$ exit logout There are stopped jobs. zhangyunchendeMacBook-Pro:.ssh zhangyunchen$ exit logout Saving session... ...copying shared history... ...saving history...truncating history files... ...completed. host "Centos" HostName 192.168.0.114 User root Port 22 [进程已完成]~

1.5 SSH的免密码登录——SSH KEY

1. 我们往往使用非对称加密的方式生成公钥
2. 私钥主要存放在本地~/.ssh目录
3. 公共密钥对外开放，放置在服务器的~/.ssh/authorized_keys

Linux下，我们通过SSH里面自带的ssh-keygen -t rsa/dsa来生成ssh key； Last login: Mon Apr 16 21:19:28 on ttys000 zhangyunchendeMacBook-Pro:~ zhangyunchen$ cd ~/.ssh zhangyunchendeMacBook-Pro:.ssh zhangyunchen$ ssh- ssh-add ssh-agent ssh-copy-id ssh-keygen ssh-keyscan zhangyunchendeMacBook-Pro:.ssh zhangyunchen$ ssh- ssh-add ssh-agent ssh-copy-id ssh-keygen ssh-keyscan zhangyunchendeMacBook-Pro:.ssh zhangyunchen$ ssh-keygen -t rsa Generating public/private rsa key pair. Enter file in which to save the key (/Users/zhangyunchen/.ssh/id_rsa): cent_rsa Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in cent_rsa. Your public key has been saved in cent_rsa.pub. The key fingerprint is: SHA256:T/9j0NxcnE7Lzysf5aaI+ek/WCJyAp4u68kFsneK1Gc zhangyunchen@zhangyunchendeMacBook-Pro.local The key's randomart image is: +---[RSA 2048]----+ | | | | | ..| | . oo| | . .. oS . o+o+| | + .o ooo.o +=+| | o o.E +...= o+| | . +.B. o.=+o+| | ..*o oo=o*=.| +----[SHA256]-----+ zhangyunchendeMacBook-Pro:.ssh zhangyunchen$ ls cent_rsa cent_rsa.pub config known_hosts zhangyunchendeMacBook-Pro:.ssh zhangyunchen$