Fail2ban可以防止惡意的一些try attach，當try太多次時，會主動阻檔
記得要先yum upgrade , yum update
1.先增加EPLE (Extra Packages for Enterprise Linux)
sudo yum install epel-release
2.安裝fail2ban
sudo yum install fail2ban
3.設定啟動時開啟fail2ban (fail2ban start on boot)
sudo systemctl enable fail2ban
4.啟動fail2ban
sudo systemctl start fail2ban
就完成安裝了，再來需要做一些預設值的設定
sudo nano /etc/fail2ban/jail.local
