[root@lnmp src]# ssh-keygen -t rsaGenerating public/private rsa key pair.Enter file in which to save the key (/root/.ssh/id_rsa): Created directory ‘/root/.ssh‘.Enter passphrase (empty for no passphrase): ＃这里设入密码123456Enter same passphrase again: #再次输入密码123456Your 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:90:e2:92:f5:73:09:46:d1:30:74:98:68:e1:38:bd:c5 root@lnmpThe key‘s randomart image is:+--[ RSA 2048]----+|    .+**.        ||   +ooo+.        ||  o.= E          ||   = * o .       ||  o o o S        ||   .   o         ||                 ||                 ||                 |+-----------------+

[root@lnmp src]# ls /root/.ssh/id_rsa.pub /root/.ssh/id_rsa.pub

[root@lnmp src]# cat /root/.ssh/id_rsa.pub ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEApcgmdimrk/4Jios2x4lhOuRuP2LWcAcydTOicDqIyRo8jMgH0X8om5nXU/rYan+nZN/9CNsy7OvpRWUDIiaDA3vPluAfdRZjS9mmaDhz4XrvhLU5NLCzCg30oOJj7dHTNSfx5T5cdpIY5fQqAnvDotCxeNXe5L7qf8pW8GQvhl3tjr3NMvQrTHle0MJ3OIn6sW6tH8Szc0T1Ctsny6wQqqrwd+DG+5PW27feM9pPNoKsLKxS8jBM3pYcXbgmlPD0OqCIMl7Up26ELQEfdddj2A1zdJFSXd4bji+I9CTwx2Rqb+d3K0JUs9l12KLDK6vSf4IpUi0ju+/800Fejawhbw== root@lnmp

[root@lnmp src]# ssh-copy-id -i /root/.ssh/id_rsa.pub root@192.168.1.12The authenticity of host ‘192.168.1.12 (192.168.1.12)‘ can‘t be established.RSA key fingerprint is 5e:5b:d3:54:cd:99:74:40:a1:45:f2:ed:9c:ac:97:57.Are you sure you want to continue connecting (yes/no)? yesWarning: Permanently added ‘192.168.1.12‘ (RSA) to the list of known hosts.root@192.168.1.12‘s password: ＃输入192.168.1.12的登录密码Now try logging into the machine, with "ssh ‘root@192.168.1.12‘", and check in:  .ssh/authorized_keysto make sure we haven‘t added extra keys that you weren‘t expecting.

[root@ok ~]# ls ~/.ssh/authorized_keys /root/.ssh/authorized_keys[root@ok ~]# cat ~/.ssh/authorized_keys ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEApcgmdimrk/4Jios2x4lhOuRuP2LWcAcydTOicDqIyRo8jMgH0X8om5nXU/rYan+nZN/9CNsy7OvpRWUDIiaDA3vPluAfdRZjS9mmaDhz4XrvhLU5NLCzCg30oOJj7dHTNSfx5T5cdpIY5fQqAnvDotCxeNXe5L7qf8pW8GQvhl3tjr3NMvQrTHle0MJ3OIn6sW6tH8Szc0T1Ctsny6wQqqrwd+DG+5PW27feM9pPNoKsLKxS8jBM3pYcXbgmlPD0OqCIMl7Up26ELQEfdddj2A1zdJFSXd4bji+I9CTwx2Rqb+d3K0JUs9l12KLDK6vSf4IpUi0ju+/800Fejawhbw== root@lnmp

[root@lnmp src]# ssh 192.168.1.12Enter passphrase for key ‘/root/.ssh/id_rsa‘: ＃输入刚才生成公钥的时候，设的密码123456如果当时没设的话就是空！！！Last login: Sun Sep 11 16:32:41 2016 from 192.168.1.103

root@lnmp .ssh]# lsid_rsa  id_rsa.pub  known_hosts[root@lnmp .ssh]# rm id_rsarm: remove regular file `id_rsa‘? y删除远程机上的私钥：[root@ok .ssh]# lsauthorized_keys  known_hosts  known_hosts.bak[root@ok .ssh]# rm authorized_keys rm: remove regular file `authorized_keys‘? y

[root@lnmp .ssh]# rm id_rsarm: remove regular file `id_rsa‘? y[root@lnmp .ssh]# cd[root@lnmp ~]# ssh-keygen -t rsaGenerating public/private rsa key pair.Enter file in which to save the key (/root/.ssh/id_rsa): Enter passphrase (empty for no passphrase): ＃这里是空的话，就真正实现了，无需输入密码，登录远程主机Enter same passphrase again: 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:c9:fe:64:6a:7c:e1:2a:ba:aa:6e:2c:f0:ee:83:7d:af root@lnmpThe key‘s randomart image is:+--[ RSA 2048]----+|                 ||                 ||                 ||       . .       ||        S        ||.      .  .      ||o+     ...o.     ||oo+ . . o=o      ||==++E=.ooo.      |+-----------------+[root@lnmp ~]# ls ~/.ssh/id_rsa       id_rsa.pub   known_hosts  [root@lnmp ~]# ls ~/.ssh/id_rsa/root/.ssh/id_rsa[root@lnmp ~]# cat ~/.ssh/id_rsa-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----

[root@lnmp ~]# ssh-copy-id -i ~/.ssh/id_rsa.pub root@192.168.1.12root@192.168.1.12‘s password: Now try logging into the machine, with "ssh ‘root@192.168.1.12‘", and check in:  .ssh/authorized_keysto make sure we haven‘t added extra keys that you weren‘t expecting.

[root@ok ~]# cat ~/.ssh/authorized_keys ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAxtlnozvT2OxoTS6XARo25G0moRaDvx7IQoMqMGpLYkN1z3vtgPWWYBj9aLh1a6Y5ziWuYV7oKnHmGa6qAjYlHv6v3/Z2qwzvJ9nEiqEaEesHWspUIr5h7hdLf21b569zbRrQf+myqSByuOUjfLaaJiMWIqKHxaKGwNwK5T0pKR5kkIVJI2N1nhEXi+i8yP67qsRtfr7S3ofwbmgmnjT5Ly1wq09dOymAz3xeeriQ3Ke3G+LhC6qEj4oFfIu95r/jPqnIGxKRJGa15tbmLn1JSBEkl0OhMSA2FfjJQqH3PAfd2J/UMduLNBEzCWcoTIGbDjNDUmTbO9mx5Kk3uRyFCQ== root@lnmp

[root@lnmp ~]# ssh 192.168.1.12Last login: Sun Sep 11 22:38:43 2016 from 192.168.1.105