RE: Webserver on a DMZ still needed?

["Robert D. Holtz - Lists" <robert.d.holtz () gmail com>]

Your suggestion of placing the server behind the firewall and opening up SSH
and SMTP is ideal.  We used static NAT mappings to make the OWA visible to
the outside world.

I did this exact setup for a charity and it worked fine.

As for the front end recommendation this does add some complexity but if the
charity is a 501(c) they can get MS licenses for pennies on the dollar.  

Another Windows and an Exchange server license were < $50.00 from what I
recall.

I would still place the front end box behind a firewall too.

-----Original Message-----
From: Peter Marshall [mailto:Peter.Marshall () gtsi com] 
Sent: Tuesday, September 05, 2006 11:32 AM
To: Davie Elliott - Eluse; security-basics () securityfocus com
Subject: RE: Webserver on a DMZ still needed?

It is still recommended to have your exchange box (and any other outward
accessible services) hosted in a DMZ to prevent access to the internal
segment if they are compromised.  If you do put the exchange box in the
DMZ, however, you need to open up a bunch of ports to allow the exchange
box to query the global catalog, perform authentication, etc. which, to
a certain degree, removes the safety added by having it in the DMZ in
the first place.  MS recommends using front end/back end exchange
servers coupled with an ISA server to do it by the book but this is
expensive and complicated for a small/mid sized organization.  Many
small/mids simply place the exchange server on the inside and only open
up tcp 25 (SMTP) and TCP 443 (HTTPS for OWA) to that box.

In your instance, since the exchange box is also a DC, I would not
recommend putting it into the DMZ.  Technically, you should split those
roles for performance and security but again, budget is sometimes more
important than doing everything by the book.


Cheers, 

-----Original Message-----
From: Davie Elliott - Eluse [mailto:delliott () eluse co uk] 
Sent: Sunday, September 03, 2006 7:43 AM
To: security-basics () securityfocus com
Subject: Webserver on a DMZ still needed?

Hi all,

I have been working as a systems admin for a charity for about 3 years,
I have no schooling in network I have learnt everything myself. During
my research I read that servers with public services should be put on a
separate subnet which is used as a DMZ (such as POP3, SMTP, webserver
ect).

Recently I have left that charity and a network company is taking over
the administration, and they want to put the Exchange (email) server on
the trusted network subnet (the network has a smoothwall firewall, so
there are literally 2 separate networks). My question is this: does the
Exchange server definatly, need to be put in the DMZ? Or should
Microsoft have patched all the vulnerabilities by now? There isn't any
other software on the server, such as forums which I see have
vulnerabilities found just about ever day.

Secondly, if the Exchange server is on the DMZ subnet, how do you get it
to interact securely with the Domain Controller on the secure subnet?
When I built the network, I made the Exchange server its own Domain
Controller.

Thanks for your advice,

Davie Elliott



------------------------------------------------------------------------
---
This list is sponsored by: Norwich University

EARN A MASTER OF SCIENCE IN INFORMATION ASSURANCE - ONLINE The NSA has
designated Norwich University a center of Academic Excellence in
Information Security. Our program offers unparalleled Infosec management
education and the case study affords you unmatched consulting
experience. 
Using interactive e-Learning technology, you can earn this esteemed
degree, without disrupting your career or home life.

http://www.msia.norwich.edu/secfocus
------------------------------------------------------------------------
---


---------------------------------------------------------------------------
This list is sponsored by: Norwich University

EARN A MASTER OF SCIENCE IN INFORMATION ASSURANCE - ONLINE
The NSA has designated Norwich University a center of Academic Excellence 
in Information Security. Our program offers unparalleled Infosec management 
education and the case study affords you unmatched consulting experience. 
Using interactive e-Learning technology, you can earn this esteemed degree, 
without disrupting your career or home life.

http://www.msia.norwich.edu/secfocus
---------------------------------------------------------------------------


---------------------------------------------------------------------------
This list is sponsored by: Norwich University

EARN A MASTER OF SCIENCE IN INFORMATION ASSURANCE - ONLINE
The NSA has designated Norwich University a center of Academic Excellence 
in Information Security. Our program offers unparalleled Infosec management 
education and the case study affords you unmatched consulting experience. 
Using interactive e-Learning technology, you can earn this esteemed degree, 
without disrupting your career or home life.

http://www.msia.norwich.edu/secfocus
---------------------------------------------------------------------------