使用ssh公钥密钥自动登陆linux服务器

[root@server ~]# ssh-keygen -b 1024 -t rsa
Generating public/private rsa key pair.
#提示正在生成rsa密钥对
Enter file in which to save the key (/home/usrname/.ssh/id_dsa):
#询问公钥和私钥存放位置，默认位置回车即可
Enter passphrase (empty for no passphrase):
#询问输入私钥密语，输入密语
Enter same passphrase again:
#再次提示输入密语确认
Your identification has been saved in /home/usrname/.ssh/id_dsa.
#提示公钥和私钥已经存放在/root/.ssh/目录下
Your public key has been saved in /home/usrname/.ssh/id_dsa.pub.
The key fingerprint is:
x6:68:xx:93:98:8x:87:95:7x:2x:4x:x9:81:xx:56:94 root@server
#提示key的指纹

[root@server ~]# scp .ssh/id_dsa.pub remote_usrname@192.168.0.2:
#比如你想使用用户peter登陆，则remote_usrname请以peter代替

[peter@client ~]$ ls
id_rsa.pub
[peter@client ~]$ mkdir ~/.ssh
#如果当前用户目录下没有 .ssh 目录，请先创建目录
[peter@client ~]$ chmod 700 ~/.ssh
[peter@client ~]$ mv id_rsa.pub ~/.ssh
[peter@client ~]$ cd ~/.ssh
[peter@client ~]$ cat id_rsa.pub >> authorized_keys2
[peter@client ~]$ rm -f id_rsa.pub
[peter@client ~]$ chmod 600 authorized_keys2
[peter@client ~]$ ls -l
total 4
-rw------- 1 peter peter 225 Oct 10 11:28 authorized_keys2

[root@server ~]# ssh peter@192.168.0.2
Enter passphrase for key '/root/.ssh/id_rsa': #提示输入密码短语，请输入刚才设置的密码短语
Last login: Sun Oct 10 11:32:14 2010 from 192.168.0.1
[peter@client ~]$

[root@server ~]# ssh-agent
SSH_AUTH_SOCK=/tmp/ssh-vEGjCM2147/agent.2147; export SSH_AUTH_SOCK;
SSH_AGENT_PID=2148; export SSH_AGENT_PID;
echo Agent pid 2148;

[root@server ~]# SSH_AUTH_SOCK=/tmp/ssh-vEGjCM2147/agent.2147; export SSH_AUTH_SOCK;
[root@server ~]# SSH_AGENT_PID=2148; export SSH_AGENT_PID;
[root@server ~]# printenv | grep SSH
#检查 ssh 环境变量是否已经加入当前会话的环境变量
SSH_AGENT_PID=2148
SSH_AUTH_SOCK=/tmp/ssh-vEGjCM2147/agent.2147

[root@server ~]# eval `ssh-agent`
Agent pid 2157
[root@server ~]# printenv | grep SSH
#检查 ssh 环境变量是否已经加入当前会话的环境变量
SSH_AGENT_PID=2148
SSH_AUTH_SOCK=/tmp/ssh-vEGjCM2147/agent.2147

[root@server ~]# ssh-add ~/.ssh/id_dsa
Enter passphrase for /home/user/.ssh/id_dsa:
#输入你的密码短语
Identity added: /home/user/.ssh/id_dsa (/home/user/.ssh/id_dsa)
[root@server ~]# ssh-add -l
#查看 ssh代理的缓存内容
1024 72:78:5e:6b:16:fd:f2:8c:81:b1:18:e6:9f:77:6e:be /root/.ssh/id_rsa (RSA)

[root@server ~]# ssh peter@192.168.0.2
Last login: Sun Oct 10 11:32:45 2010 from 192.168.0.1
[peter@client ~]$

[root@server ~]# ssh-agent -k
unset SSH_AUTH_SOCK;
unset SSH_AGENT_PID;
echo Agent pid 2148 killed;
[root@server ~]# ssh-add -l
#查看一下，缓存里已经没有了密钥了
The agent has no identities.