[ale] iptables rules

Chris Fowler cfowler at outpostsentinel.com
Wed Aug 4 15:23:14 EDT 2004


On Wed, 2004-08-04 at 15:16, Stephan Uphoff wrote:
> Repeat after me:
> 	The INPUT chain is for a packet with the box itself as a destination
> 	The OUTPUT chain is for locally generated packets
> 	The FORWARD chain is for routed packages.
> 	Routed packages will not go through the INPUT or OUTPUT chains.

Thanks for that clarification.

> 
> This is different than it was with the old "ipchains".
> 
> /sbin/iptables -A FORWARD -p tcp -i ${PRIVATE} -s 192.168.254.0/24 -d
>  0.0.0.0/0 --dport 25 -j DROP

Yep.  That is what I had to do.


> 
> 	Stephan
> 
> 
> > Here is one rule set:
> > /sbin/iptables -A INPUT -p tcp -i ${PRIVATE} -s 192.168.254.0/24 -d
> > 192.168.1.254/32 --dport 25 -j ALLOW
> > /sbin/iptables -A INPUT -p tcp -i ${PRIVATE} -s 192.168.254.0/24 -d
> > 0.0.0.0/0 --dport 25 -j DROP
> > 
> > 
> > Should'nt the exception be before the rule?
> > 
> > 
> > On Wed, 2004-08-04 at 14:45, Christopher Fowler wrote:
> > > I have a machine on the network that I need to protect my bandwidth
> > > from.  This is a windows box and it is clear to me that it can not be
> > > trusted.
> > >
> > > My firewall is 192.168.1.254 and I want it to be able to go to port 25
> > > of that machine but not out the public interface.  I also want to block
> > > all outgoing ports other than 80.
> > >
> > > 2 Trojans were found on this machine and I think it has become a spam
> > > box.
> > >
> 



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