Re: Firewall and DMZ topology

["Daniel B. Cid" <danielcid () yahoo com br>]

There are many reasons. The first of all, in this situation:

> internet -->  Firewall --> LAN
>                              --> DMZ

You need to pass  through you LAN to access the DMZ ... I dont need
to say anithing more. The purpose of a DMZ is to isolate the public
servers from outside the LAN. If someone hacks the DMZ will not be
able to access the LAN.

> internet --> Outer Firewall --> DMZ --> Inner Firewall --> LAN

In this other situation you  need to pass through the DMZ to access the
LAN, so all conections from the LAN to the INTERNET will pass in the
DMZ.. if someone compromise the DMZ will be able to snif the conections
to the internet and a lot of other things ...

->The "real" purpose of a DMZ is to isolate your public servers, nothing
more.

[]`s

Daniel B. Cid


> On Mon, 2003-06-09 at 20:53, Chris Berry wrote:
> > From: Christopher Ingram <cmi () crystalsands net>
> > So, the below setup is not decent for a corporate LAN. Ideally, the DMZ 
> > should sit on a seperate connection to the Internet from the rest of the 
> > network, using a different ISP and therefore, different IP block. This 
> > provides the most isolation.
>
> I'm afraid I don't see how that:
>
> internet --> Firewall --> Lan
>
> internet --> Firewall --> DMZ
>
> would be any more secure than this:
>
> internet --> Outer Firewall --> DMZ --> Inner Firewall --> LAN
>
> or this:
>
> internet -->  Firewall --> LAN
>                              --> DMZ
>
> which are the setups that I've seen.  Can you give some 
> justification/explanation on why you think that would be better?
>
> Chris Berry
> compjma () hotmail com
> Systems Administrator
> JM Associates
>
> "All I want is a few minutes alone with the source code for the universe and 
> a quick recompile."
>
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