Ubuntu
#查看防火牆狀態
sudo ufw status
#開啟防火牆
sudo ufw enable
#關閉防火牆
sudo ufw disable
CentOs
#查看防火牆狀態
systemctl status firewalld
# 開啟
sudo service firewalld start
# 重啟
sudo service firewalld restart
# 關閉
sudo service firewalld stop