iptables help

[Jessica Zhu]

Hi,

I tried to customize and set up firewall using iptables on Red Hat 
Enterprise Linux ES release 3. The file /etc/sysconfig/iptables got 
edited. After I finished editing, I restarted service using 
/etc/init.d/iptables restart or service iptables restart. However, though 
it's got successfully restarted, when I checked the status, none of my 
editing taking effection. 
It's weired. For example, the default chain INPUT, OUTPUT and FORWARD all 
are ACCEPT, down in new iptables I edited, it's like as follows,

*filter
:INPUT DROP
:FORWARD DROP
:OUTPUT ACCEPT [0:0]

But nothing take effection after iptables got restarted. What happened?

Jessica