DMZ Security?
- From: "Goktug Yildirim" <yildirim@xxxxxxxxxxxxxxx>
- To: "[ISAserver.org Discussion List]" <isalist@xxxxxxxxxxxxx>
- Date: Sun, 17 Feb 2002 04:00:36 +0200
Hello,
I have some questions about not a specific problem,configuration or
installation but I am looking for answers of a "WHY?" list. I don't mean
to bother anyone but I cant help myself to look deeper of these
questions. In my opinion these are really important basic questions to
ask yourself before designing an internet/intranet security.
1. WHY back-to-back DMZ is more secure than the 3-NIC DMZ?
What is my advantage of buying another license and dealing with lots of
configurations instead of working with 3-NIC DMZ?
Is it only because of isolating the subnets not only with a software
code but also physically? And if it is so, don't we have to trust that
code? If it fails physical isolation saves me really?? Because I have
another failed or ready to be hacked firewall software at the other end!
2. WHY is it a DMZ security violation to have an internal domain member
server in the back-to-back DMZ scenario? If I ask this question in a
very simple way, WHAT is the difference between a hacked member server
and a hacked stand-alone server?
Front-End<->Back-End Exchange 2000 architecture requires the Front-End
Exchange server to be as a member server. Also Microsoft has an article
to deal with this configuration which even lists the desired ports to be
opened. IF this is a DMZ violation WHY MS violates its own firewall
security?
3. WHY is it more secure to chain the ISA firewalls?
What is security failure or hole if I don't chain the internal and
external firewalls in a back-to-back DMZ scenario?
4. IF I open a VPN tunnel inside from one of the DMZ server to reach
some of the resources at the internal domain is it a DMZ security
violation or is it better and more secure than creating lots of packet
filters and tons of configuration for that DMZ server?
If I configure a packet filter only for that server and if someone
simulates a IP packet that has the same source IP as the DMZ server's IP
it can reach that specific resource. But if I configure this server as a
L2TP VPN client properly don't I make sure of incoming source exactly?
5. WHY publishing a server is more secure than putting it in the DMZ?
(comparison of public IP DMZ and private IP DMZ).
What is the difference between ISA server publishing and DMZ server
publishing? When you publish a server it means that someone can open a
session to that server and can exploit whatever he/she wants if it is
possible. Isn't the same for DMZ server publishing? What are the
benefits or losses of publishing a server against DMZ server publishing?
I know I have to read books and I can find these topics. However, I just
need some push or a start to go further. Answers or comments with one or
two sentences would make this great!
Thanks and regards for anyone who even reads these,
GOKTUG YILDIRIM
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