一、情景
公司刚上几台Linux，现在要把主机之间实现都能远程ssh免密码登陆。
二、原理
很简单，使用ssh-keygen在主机A上生成private和public密钥，将生成的public密钥拷贝到远程机器主机B上后，就可以使用ssh命令无需密码登录到另外一台机器主机B上。
三、步骤
主机A：
1.生成公钥和私钥文件id_rsa和id_rsa.pub (敲三下回车即可)。
- [root@bogon ~]# ssh-keygen -t rsa
- Generating public/private rsa key pair.
- Enter file in which to save the key (/root/.ssh/id_rsa):
- Enter passphrase (empty for no passphrase):
- 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:
- 67:da:0d:79:e0:d6:2b:cd:7d:22:af:51:7e:9c:75:fe root@bogon
- The key's randomart image is:
- +--[ RSA 2048]----+
- | |
- | |
- | . |
- | . + |
- | S B o . o|
- | * * = o+|
- | . o B +.=|
- | . + +.|
- | ... E|
- +-----------------+
2.ssh-cop-id命令会将指定的公钥文件复制到远程计算机。
- [root@bogon ~]# ssh-copy-id -i ~/.ssh/id_rsa.pub root@10.1.250.166
- The authenticity of host '10.1.250.166 (10.1.250.166)' can't be established.
- RSA key fingerprint is c8:9d:6d:92:55:77:3d:3e:af:f5:cb:18:80:5a:47:93.
- Are you sure you want to continue connecting (yes/no)? yes
- Warning: Permanently added '10.1.250.166' (RSA) to the list of known hosts.
- reverse mapping checking getaddrinfo for bogon [10.1.250.166] failed - POSSIBLE BREAK-IN ATTEMPT!
- root@10.1.250.166's password: <主机B的登陆密码>
- Now try logging into the machine, with "ssh 'root@10.1.250.166'", and check in:
- .ssh/authorized_keys
- to make sure we haven't added extra keys that you weren't expecting.
3.然后ssh登陆主机B验证是否需要密码。
- [root@localhost ~]# ssh 10.1.250.166
- reverse mapping checking getaddrinfo for bogon [10.1.250.166] failed - POSSIBLE BREAK-IN ATTEMPT!
- Last login: Wed Oct 21 10:05:39 2015 from 10.1.250.141
- [root@bogon ~]#
4.登陆成功后，我们需要在主机B也做下以上3步，这样就可以相互免密码ssh登陆。(如果有多台主机，每台主机都做下相同操作，以方便以后管理)。
5.权限问题
建议用其他用户做ssh登陆的话，调整目录文件权限。
设置authorized_keys权限
- chmod 644 authorized_keys
设置.ssh目录权限
- chmod 700 -R .ssh
6.要保证.ssh和authorized_keys都只有用户自己有写权限。否则验证无效。
作者：好大的刀
来源：51CTO
时间： 2024-04-26 00:12:36