今天发现有一台服务器没有配置防火墙，使用service iptables start/stop没啥反应．然后，/etc/sysconfig/iptables这个文件缺失．

防火墙配置例子：

1. # Firewall configuration written by system-config-firewall
   # Manual customization of this file is not recommended.
   *filter
   :INPUT ACCEPT [0:0]
   :FORWARD ACCEPT [0:0]
   :OUTPUT ACCEPT [0:0]
   -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
   -A INPUT -p icmp -j ACCEPT
   -A INPUT -i lo -j ACCEPT
   -A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
   -A INPUT -j REJECT --reject-with icmp-host-prohibited
   -A FORWARD -j REJECT --reject-with icmp-host-prohibited
   COMMIT

解决：

随便配置一条规则：iptables -P OUTPUT ACCEPT

service iptables save

本文转自chenzudao51CTO博客，原文链接：http://blog.51cto.com/victor2016/1912450 ，如需转载请自行联系原作者