google-authenticator

Installation way:

yum -y install google-authenticator 

Note: If you do not find, you want to install epel-release source, yum -y install epel-release

Installation way:

yum install -y git make gcc libtool pam-devel qrencode ntpdate

git clone https://github.com/google/google-authenticator-libpam.git
cd   google-authenticator-libpam/
./bootstrap.sh
./configure
make
make install

Configuring ssh

vim /etc/ssh/sshd_config

Modify the following configuration items:

ChallengeResponseAuthentication yes
UsePAM yes

Configuring PAM

vim /etc/pam.d/sshd

#%PAM-1.0
auth      required     pam_google_authenticator.so   #添加至第一行

Ssh restart

systemctl restart sshd

Configuring google authenticator
prerequisite: you need to switch to an account set up

google-authenticator

Do you want authentication tokens to be time-based (y/n)  #基于时间生成身份验证
#已经安装qrencode会产生一个二维码，二维码连接也可以URL显示
Your new secret key is ：***********   # 密钥key
#使用移动端的 authenticator 扫描二维码或者输入密钥key
#得到code from app  ：
Enter code from app (-1 to skip):   #输入得到的code，动态验证
Your emergency scratch codes are:  #  生成5 个紧急救助码
Do you want me to update your "/root/.google_authenticator" file? (y/n)  #一直确认下去
# 生成了一个 .google_authenticator 文件

your chances to notice or even prevent man-in-the-middle attacks (y/n)  #一直确认下去
Do you want to do so? (y/n)   #一直确认下去
Do you want to enable rate-limiting? (y/n)  #设置完成

#上面的意思大概为：禁止多次使用相同的身份验证，限制每30秒登录一次，移动端每30秒更新一次，移动端和客户端时间误差30秒，30秒内不能超过3次登录。

If you need to delete a user's Google verification, delete the user generated home/.google_authenticatorfile to