好久没弄了，来个最简的centos下的Iptables文件存照吧。

有最基本的作用。。

# Generated by iptables-save v1.4.7 on Wed Sep  7 14:51:32 2016
*filter
:INPUT ACCEPT [9:396]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [347:287188]
-A INPUT -i lo -j ACCEPT
-A INPUT -p tcp -m tcp --dport 22 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 21 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 80 -j ACCEPT
-A INPUT -p icmp -m icmp --icmp-type 8 -j ACCEPT
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A FORWARD -p tcp --syn -m limit --limit 1/s --limit-burst 5 -j ACCEPT
-A FORWARD -p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK RST -m limit --limit 1/sec -j ACCEPT
-A FORWARD -p icmp -m icmp --icmp-type 8 -m limit --limit 1/sec -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT
# Completed on Wed Sep  7 14:51:32 2016