服务器间通过ssh使用密钥对实现无密码登录solaris,redhat,linux

hosta和hostb都必须同步完成以下操作,以hosta为例
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1、创建密钥对，两台都做
[root@hosta /]# who am i
root     pts/1        2008-04-30 12:08 (172.16.10.220)
[root@hosta /]# cd ~/.ssh
[root@hosta .ssh]# ssh-keygen -t dsa
Generating public/private dsa key pair.
Enter file in which to save the key (/root/.ssh/id_dsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_dsa.                              -------私钥名一定要叫id_dsa
Your public key has been saved in /root/.ssh/id_dsa.pub.
The key fingerprint is:
0a:13:25:19:a2:59:2c:b1:49:e6:62:90:57:07:e5:f7 root@hosta

passphrase(密钥保护) 保留为空，否则使用ssh时将要求输入passphrase(密钥保护)

2、发布公钥和获取公钥
[root@hosta .ssh]# scp id_dsa.pub hostb:/root/.ssh/hosta.key.pub
root@hostb's password:
id_dsa.pub                                            100%  600     0.6KB/s   00:00   
[root@hosta .ssh]# scp hostb:/root/.ssh/id_dsa.pub /root/.ssh/hostb.key.pub
root@hostb's password:
id_dsa.pub                                            100%  600     0.6KB/s   00:00   

3、对公钥授权两台都做
[root@hostb .ssh]# cat hosta.key.pub >>authorized_keys2                 -----对A机公钥授权,A机用私钥来登录B机
[root@hostb .ssh]# cat id_dsa.pub >>authorized_keys2                      -----可选项，本机登录本机，可不配置

如果是ssh v1版本，比如solaris 9，就使用authorized_keys文件

4、使用密钥对登录
[root@hosta .ssh]# ssh hostb
Last login: Sun Apr 27 00:04:49 2008 from 172.16.10.220

已经不用输入密码lol

[root@hostb ~]# exit
logout
Connection to hostb closed.