在CentOS8中设置SSH密钥

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最流行的两种SSH身份验证机制是基于密码的身份验证和基于公钥的身份验证。使用SSH密钥通常比传统的密码身份验证更安全和方便。

环境

客户端：CentOS8 192.168.43.137

服务端：CentOS8 192.168.43.139

创建SSH公私钥

通过输入以下命令，生成新的4096位的SSH密钥对：

[root@localhost ~]# ssh-keygen -t rsa -b 4096Generating 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:SHA256:ycOtSDK8ud2kd6EH7OxoQuc1BFb1HJ3T/kvAQJt0LrI root@localhost.localdomainThe key's randomart image is:+---[RSA 4096]----+|       ...oo.o o ||      o   .+=.+ .||     . . . +=. o ||   .   o.oo .o  .||    + .oSE.   . .||    .*..=o.    ..||   .oo.+o+ .  . .||    .oo== o    . ||    .o+ooo       |+----[SHA256]-----+

                               
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想要验证是否生成了新的SSH密钥对，使用ls -l命令查看~/.ssh目录是否有刚才生成的文件：

[root@localhost ~]# ll ~/.ssh/total 8-rw------- 1 root root 3389 May 13 08:26 id_rsa-rw-r--r-- 1 root root  752 May 13 08:26 id_rsa.pub

                               
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将公钥复制到远程服务器，使用ssh-copy-id实用程序，输入远程服务器的root密码：

[root@localhost ~]# ssh-copy-id root@192.168.43.139/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"The authenticity of host '192.168.43.139 (192.168.43.139)' can't be established.ECDSA key fingerprint is SHA256:7O1oIOooh4NZG87aC3v1Zz/vcTXkjOhQBnlkY0CD4y0.Are you sure you want to continue connecting (yes/no)? yes/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keysPassword: Number of key(s) added: 1Now try logging into the machine, with:   "ssh 'root@192.168.43.139'"and check to make sure that only the key(s) you wanted were added.

                               
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也可以使用以下命令复制公钥：

[root@localhost .ssh]# cat ~/.ssh/id_rsa.pub | ssh root@192.168.43.139 "mkdir -p ~/.ssh && chmod 700 ~/.ssh && cat >> ~/.ssh/authorized_keys && chmod 600 ~/.ssh/authorized_keys"使用密钥登录服务器

使用以下命令登录ssh服务器：

[root@localhost ~]# ssh 192.168.43.139Last login: Tue May 12 12:33:41 2020 from 192.168.43.137

                               
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关闭密码认证

登录服务器端，关闭密码认证：

[root@localhost ~]# ssh 192.168.43.139Last login: Tue May 12 12:33:41 2020 from 192.168.43.137[root@localhost ~]# vim /etc/ssh/sshd_config搜索一下三条，将选项改为NoPasswordAuthentication noChallengeResponseAuthentication noUsePAM no

                               
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重启sshd服务：

[root@localhost ~]# systemctl restart sshd总结

可以使用同一密钥管理多个远程服务器。默认情况下，SSH的端口是TCP 22。更改默认SSH端口可降低自动攻击的风险。

本文原创地址：https://www.linuxprobe.com/centos8-ssh-private-key.html编辑：倪家兴，审核员：逄增宝