iptables 配置文件内容如下：

#1、允许22和80端口允许外部访问

#2、允许本地调用任何端口

#3、允许数据响应

#4、允许本地访问外部资源

# Generated by iptables-save v1.4.7 on Fri Apr 21 17:05:53 2023

*filter
:INPUT DROP [0:0]
:FORWARD DROP [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -p tcp -m tcp --dport 22 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 80 -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A OUTPUT -j ACCEPT
COMMIT
# Completed on Fri Apr 21 17:05:53 2023