RE: Firewall and DMZ topology

["Depp, Dennis M." <deppdm () ornl gov>]

I'm not sure how a tri-homed firewall can be just as secure as a two
firewall setup.  Consider this:

Hacker is able to penetrate your firewall and "owns" the box.  In a
tri-homed firewall, they now have direct access to your internal
network.  If this had been a two firewall setup, they would have to
compromise the second box as well.  While this may not be an issue as
they were already sucessful in owning one firewall, hopefully you have
your intrusion detection system tuned to a greater degree of sensativity
in your DMZ.  And you will be able to discover this second attempt.

I do think tri-homed firewalls are a good solution, but they are not as
secure as a two firewall solution.

Dennis Depp 

> -----Original Message-----
> From: Chris Berry [mailto:compjma () hotmail com] 
> Sent: Tuesday, June 10, 2003 2:21 PM
> To: security-basics () securityfocus com
>
> > From: "Des Ward" <des.ward () ntlworld com>
> > The second means that all traffic has to traverse your LAN 
> to get to the
> > 'Unprotected' DMZ systems and also could leave your internal 
> LAN open to
> > attack.
>
> My ASCII drawing didn't come out very well it was supposed to 
> represent a 
> tri-homed firewall, which, to the best of my knowledge is 
> just as secure as 
> a two firewall setup.
>
> Chris Berry
> compjma () hotmail com
> Systems Administrator
> JM Associates
>
> "Gold is for the mistress - silver for the maid
> Copper for the craftsman cunning in his trade.
> "Good!" said the Baron, sitting in his hall
> But steel - cold steel is master of them all." -- Rudyard Kipling
>
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