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 From:  "Neil A. Hillard" <m0n0 at dana dot org dot uk>
 To:  m0n0wall at lists dot m0n0 dot ch
 Subject:  Re: [m0n0wall] Routing to DMZ without bridging or NAT
 Date:  Thu, 27 Apr 2006 22:46:47 +0100

In message <4450DED8 dot 5060609 at febo dot com>, John Ackermann N8UR
<jra at febo dot com> writes
>I'm replacing a firewall/router based on the Linux Router Project to a
>Soekris 4801 and am considering using m0n0wall; overall it looks like a
>very good product.
>I'm trying to understand if I can replicate my current DMZ structure
>with m0n0wall.  I've looked at the FAQ and neither the DMZ-using NAT
>nor DMZ-using-bridging options really meet my needs (because I've
>recently had trouble using NAT to an internal NTP server, and I need my
>local network to be able to reach the DMZ -- those requirements seem to
>rule out the two DMZ examples in the FAQ).
>My current architecture uses NAT for the internal network, but simple
>IP routing for the DMZ, passing through the ipfilter.  Also, I use the
>same IP address for the WAN and the DMZ interfaces on the firewall box
>(ie, my provider gives me a block of five static addresses; the bottom
>one is picked off for the firewall/router, with the other four passed
>on to the DMZ interface).
>In other words:  eth0 is the wan, with address xx.xx.xx.238; eth1 is
>the DMZ, also using address xx.xx.xx.238; eth2 is the LAN, using NAT
>and address 192.168.x.x.  Traffic for addresses xx.xx.xx.239-.242 goes
>through the packet  filter and out the DMZ port.
>Can m0n0wall: (a) use the same IP address on both the WAN and DMZ
>interface, and (b) do simple routing and firewalling between WAN and
>DMZ without NAT or bridging?

You can't have multiple interfaces with the same IP address.

If you're thinking that there's a problem accessing devices on an
interface that is bridge with WAN then there really isn't a problem.

The documentation states that you cannot access devices on the bridged
interface from a _NAT'd_ interface.  Simply enable advanced outbound NAT
and ensure that LAN -> OPT traffic isn't NAT'd but LAN -> WAN is and
you'll be laughing.

I'm using that exact setup on my m0n0wall (and have been for over a
year).  I have a SIP server on OPT1 and it's setup like this because of
NAT issues with SIP.  Now my SIP traffic isn't subject to NAT.



Neil A. Hillard                E-Mail:   m0n0 at dana dot org dot uk