ssh 无密码登录要使用公钥与私钥。linux下可以用用ssh-keygen生成公钥/私钥对,下面我以CentOS为例。
有机器A(192.168.1.155),B(192.168.1.181)。现想A通过ssh免密码登录到B。
1.在A机下生成公钥/私钥对。
[chenlb@A ~]$ ssh-keygen -t rsa -P ”
-P表示密码,-P ” 就表示空密码,也可以不用-P参数,这样就要三车回车,用-P就一次回车。
它在/home/chenlb下生成.ssh目录,.ssh下有id_rsa和id_rsa.pub。
2.把A机下的id_rsa.pub复制到B机下,在B机的.ssh/authorized_keys文件里,我用scp复制。
[chenlb@A ~]$ scp .ssh/id_rsa.pub chenlb@192.168.1.181:/home/chenlb/id_rsa.pub
chenlb@192.168.1.181’s password:
id_rsa.pub 100% 223 0.2KB/s 00:00
chenlb@192.168.1.181’s password:
id_rsa.pub 100% 223 0.2KB/s 00:00
由于还没有免密码登录的,所以要输入密码。
3.B机把从A机复制的id_rsa.pub添加到.ssh/authorzied_keys文件里。
[chenlb@B ~]$ cat id_rsa.pub >> .ssh/authorized_keys
[chenlb@B ~]$ chmod 600 .ssh/authorized_keys
[chenlb@B ~]$ chmod 600 .ssh/authorized_keys
authorized_keys的权限要是600。
4.A机登录B机。
[chenlb@A ~]$ ssh 192.168.1.181
The authenticity of host ‘192.168.1.181 (192.168.1.181)’ can’t be established.
RSA key fingerprint is 00:a6:a8:87:eb:c7:40:10:39:cc:a0:eb:50:d9:6a:5b.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added ‘192.168.1.181’ (RSA) to the list of known hosts.
Last login: Thu Jul 3 09:53:18 2008 from chenlb
[chenlb@B ~]$
The authenticity of host ‘192.168.1.181 (192.168.1.181)’ can’t be established.
RSA key fingerprint is 00:a6:a8:87:eb:c7:40:10:39:cc:a0:eb:50:d9:6a:5b.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added ‘192.168.1.181’ (RSA) to the list of known hosts.
Last login: Thu Jul 3 09:53:18 2008 from chenlb
[chenlb@B ~]$
第一次登录是时要你输入yes。
现在A机可以无密码登录B机了。
小结:登录的机子可有私钥,被登录的机子要有登录机子的公钥。这个公钥/私钥对一般在私钥宿主机产生。上面是用rsa算法的公钥/私钥对,当然也可以用dsa(对应的文件是id_dsa,id_dsa.pub)
想让A,B机无密码互登录,那B机以上面同样的方式配置即可。