安装UFW

在安装之前先关闭自带的firewalld

# 停止并关闭 firewalld
sudo systemctl stop firewalld
sudo systemctl disable firewalld

# 安装并开启 ufw
sudo yum install ufw
sudo systemctl enable ufw
sudo systemctl start ufw

检查 ufw 是否启用

sudo ufw status

会看到如下内容

Status: active

     To                           Action      From
     --                           ------      ----
[ 1] 22/tcp                       ALLOW IN    Anywhere
[ 2] 8080/tcp                     ALLOW IN    Anywhere
[ 3] 443/tcp                      ALLOW IN    Anywhere

放行端口（8080）

# tcp
sudo ufw allow 8080/tcp
# udp
sudo ufw allow 8080/udp

移除放行端口（8080）

sudo ufw delete 2
# 或者
sudo ufw delete allow 8080/tcp