RE: Exchange Server and External Access

["Nero, Nick" <Nick.Nero () disney com>]

VPNS are bad to use for mail.  As people are finding out this week, it
exposes way too many ports (TCP 135 particulary) just so you can make
native calls to the mail server.  Web mail is a much better solution
(OWA for 2000 is very good and OWA for Exchange 2003 is almost exactly
as full featured as the Outlook 2003 client) for security reasons.  Add
the benefit that no company information actually leaves the box and the
solution really shines.

A workstation/laptop that is used for VPN has to be as secure as an
internal machine.  So after apply your Windows 2000 GPO's, A-V updates,
service patches and hotfixes, the TCO of the solution gets out of
control.  Unless someone just HAD to have native port access to an app
server, I would stay away from VPN.  Go for Term.Services/Citrix before
you go there.

Nick Nero
CISSP
The Walt Disney Company

-----Original Message-----
From: Nick Duda [mailto:nduda () VistaPrint com] 
Sent: Monday, August 25, 2003 12:23 PM
To: jsansi () ritzfoodservice com; Cherian M. Palayoor;
security-basics () securityfocus com
Subject: RE: Exchange Server and External Access

The reason why we didn't do that in my location was ease of
connectivity. Principals and executives like to just pop open a browser
and get email. Adding them to the corporate vpn would require vpn
software installs..etc. Not to mention all the different hotels during
traveling tend to block a lot of vpn traffic.

- Nick

-----Original Message-----
From: Jimmy Sansi [mailto:jsansi () ritzfoodservice com]
Sent: Friday, August 22, 2003 5:09 PM
To: 'Cherian M. Palayoor'; security-basics () securityfocus com
Subject: RE: Exchange Server and External Access



Why not configure a VPN into the network. Easier then setting up another
server in the DMZ, plus users can have access to other network resources
as well.

-Jimmy

-----Original Message-----
From: Cherian M. Palayoor [mailto:cpalayoor () cwalkergroup com]
Sent: Friday, August 22, 2003 12:11 PM
To: security-basics () securityfocus com
Subject: Exchange Server and External Access


Hi,

We presently use the Std edition of Exchange 2000 as a mail server for
our internal users, behind the Firewall.

However we would like to grant mailbox access to external users outside
the Firewall.

What would be the most secure and efficient method of accomplishing
this. 

One stream of thought that I have been entertaining is having a separate
Exchange/Mail  Server on the DMZ.

Now this solution would result in having to maintain 2 separate
mailboxes for internal and external users. This creates problems for
users who would access their emails from both inside and outside the
office.

How can I workaround this problem.

Thanks in advance for any suggestions.

Regards

CP


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Attend Black Hat Briefings & Training Federal, September 29-30 (Training),
October 1-2 (Briefings) in Tysons Corner, VA; the world's premier
technical IT security event.  Modeled after the famous Black Hat event in
Las Vegas! 6 tracks, 12 training sessions, top speakers and sponsors.
Symantec is the Diamond sponsor.  Early-bird registration ends September 6.Visit us: www.blackhat.com
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