Iptables Question

[Jack Bowling]

On Fri, Jun 01, 2007 at 09:58:16AM -0400, Rashkae wrote:
> Waqas Toor wrote:
> > Hello Ubuntuers,
> > 
> > i have written a script to setup a firewall for me
> > 
> > the script is
> > ====================================
> > #! /bin/bash
> > 
> > #blocking every thing
> > 
> > /sbin/iptables -A INPUT -p all -j DROP
> > /sbin/iptables -A FORWARD -p all -j DROP
> > 
> > #allowing only my MACs
> > 
> > for MAC in `cat ./macclist`
> > do
> >         /sbin/iptables -A INPUT -m mac --mac-source $MAC -p all -j ACCEPT
> >         /sbin/iptables -A INPUT -m mac --mac-source $MAC -j ACCEPT
> > done
> > 
> 
> A Packet will travel to the first rule it matches.  In this case, your 
> first matching rule is -A INPUT -p all and the action is DROP, end of line.
<snip>

As well, it is considered bad form for any firewall bash script to not
clear the existing tables before loading their own.

Jack