Nicolas Riendeau wrote:

>  > First off, do you NEED some of your servers on public IPs to be in
>>  your internal network instead of the DMZ ?
>
>Yes... Not doing it would only be a temporary solution that I would like
>to replace with what I described as soon as I could...
>
>Is the problem the way the subnet traffic is routed to me or that I want
>to map those IP to more than one subnet? I know we had/have servers
>mapped like that at work so there must be a way to do it...
>
>(OK the firewall we had/have at work were/are not Shorewall but I would
>be very surprised if it was able to do something Shorewall could not...)

Well it's possible they used private addressing in the DMZ (it's not 
an uncommon thing to do) and port-forward traffic as required. That 
way you can direct any public Ip to any host in any subnet - but you 
still get all the issues relating to using NAT.
Also, at work you may well be using split-horizon DNS, or just using 
different names from the inside, or have the firewall set up to allow 
redirection of traffic from internal addresses to the external 
addresses handled properly (Shorewall can do this, see :
http://shorewall.net/FAQ.htm#DNS-DNAT


>  > If you do, can these be dual homed ?
>
>Dual homing them as in putting two NIC cards in them and put them on
>both the DMZ and internal network? Doesn't that somehow defeat the
>purpose of having the two subnets?

In part - yes it defeats the security issue in that if someone gains 
access to one of the dual homed servers then they also get access to 
your internal network. But that only applies to the dual homed ones.

But it's a fact of life that security and operational requirements 
sometimes conflict. In extreme, you could argue that the only way to 
be completely secure would be to unplug all the network cables from 
all the devices - though that would somewhat interfere with 
operational needs !

With so much that relies on broadcasts to find things, it can 
sometimes be a pain (though seldom too difficult) to get things 
working.

>  > Probably the easiest setup would be to have your DMZ using the public
>>  subnet, and then route between WAN and DMZ (no NAT involved).
>>  Obviously your firewall will use up one of your public addresses.
>
>There would be NAT involved for all the PCs on the internal network
>though, right?

Yes, just not for the DMZ.

-- 
Simon Hobson

Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
Christmas stocking fillers. Some available as e-books.

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