#头两行是注释说明# Firewall configuration written by system-config-securitylevel# Manual customization of this file is not recommended.#使用filter表*filter#下面四条内容定义了内建的INPUT.FORWAARD.ACCEPT链,还创建了一个被称为RH-Firewall-1-INPUT 的新链:INPUT ACCEPT [0:0]:FORWARD ACCEPT [0:…