?
Solved

Windows 2003 SMTP Relay in a DMZ

Posted on 2004-10-07
9
Medium Priority
?
1,544 Views
Last Modified: 2008-01-09
How do I configure the networking for a SMTP Relay in a DMZ?  My DMZ sits behind a Cisco Pix 515.  As I see it I have 2 options.

1.  Either having 2 NIC, one to the DMZ and on the LAN?
2.  or set up routing rules and allow incoming and outgoing SMTP traffic on the PIX from the internet to the SMTP DMZ server and from the SMTP DMZ server to the LAN (Exchange Server).

Setting up the SMTP service (IIS, etc) should not be an issue but I'm unsure on the network setup.  I did try to setup the first senario but as soon as I set up the second nic (eather to the DMS or the Lan) I lose connectivity.

Thanks!!!
0
Comment
Question by:chilemoore
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 4
  • 3
  • 2
9 Comments
 
LVL 71

Expert Comment

by:Chris Dent
ID: 12250444

The second option is the more secure of the two, it stops any direct connections to your internal LAN from anywhere but the DMZ.

Careful with the SMTP Server that comes with IIS though, I'm pretty sure it will bounce E-mail over 2Mb.

On the Exchange server you would set it to Forward all outbound mail to the SMTP Relay Host on the DMZ.
0
 
LVL 15

Expert Comment

by:adamdrayer
ID: 12252349
>>My DMZ sits behind a Cisco Pix 515

DMZs usually do not sit behind firewalls, they are DeMilitarized.. could you explain your setup a little more?
0
 

Author Comment

by:chilemoore
ID: 12252450
Have my DMZ branching off my PIX.  Currently the only thing in the DMZ is my VPN that connects to the LAN via the Private Port, DMZ on the Public.  I do have some restrictions so it's not opened to the Internet.  Plan to put my SMTP relay in the DMZ also.  Any suggestions?  

The plan is to do option 2 above, but wondered if option 1 was duable since my VPN is set up that way.  Plus don't know if I can remotely administer the SMTP relay when it's in the DMZ due to some routing issues on the Pix 515.  That would be me VPNin (Remember VPN server is in the DMZ) and then trying to connect to the SMTP.  Not a big deal, more concerned on getting the SMTP Relay working correctly.

Thanks.
0
Veeam Disaster Recovery in Microsoft Azure

Veeam PN for Microsoft Azure is a FREE solution designed to simplify and automate the setup of a DR site in Microsoft Azure using lightweight software-defined networking. It reduces the complexity of VPN deployments and is designed for businesses of ALL sizes.

 

Author Comment

by:chilemoore
ID: 12252458
Also thought it was strange that in the 2 nic senario i lost all connectivity when I had the 2 set up (routing?)
0
 
LVL 71

Assisted Solution

by:Chris Dent
Chris Dent earned 180 total points
ID: 12252492

The main problem with Option 1 is that it completely bypasses the Firewall, the idea of putting servers in a DMZ (aside from that you can make it as secure as possible) is that, if compromised, it still can't harm your internal network.

By giving a public machine an interface on both networks you give an attacker (if successful) *full* access to the internal network.
0
 

Author Comment

by:chilemoore
ID: 12252524
even though I only alow SMTP form the firwall to the SMTP Relay in the DMZ?  Well not realy Demileterized..
0
 
LVL 15

Expert Comment

by:adamdrayer
ID: 12252595
What Chris-Dent is saying, is that if all you're gonna allow into the MailServer is SMTP, and you would physically connect it to your internal LAN, then it is now part of your internal network and not part of the LAN.  you might as well put in behind the firewall and use port forwarding.  If it's in your DMZ, by definition you want all communications with your LAN to go through te firewalls ACL
0
 
LVL 15

Accepted Solution

by:
adamdrayer earned 195 total points
ID: 12252607
>>then it is now part of your internal network and not part of the LAN
should have been
then it is now part of your internal network and not part of the DMZ
0
 

Author Comment

by:chilemoore
ID: 12912496
I finally got it going, contacted Cisco and they gave me a hand.
0

Featured Post

Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

We recently endured a series of broadcast storms that caused our ISP to shut us down for brief periods of time. After going through a multitude of tests, we determined that the issue was related to Intel NIC drivers on some new HP desktop computers …
Trying to figure out group policy inheritance and which settings apply where can be a chore.  Here's a very simple summary I've written which might help.  Keep in mind, this is just a high-level conceptual overview where I try to avoid getting bogge…
This course is ideal for IT System Administrators working with VMware vSphere and its associated products in their company infrastructure. This course teaches you how to install and maintain this virtualization technology to store data, prevent vuln…
Michael from AdRem Software explains how to view the most utilized and worst performing nodes in your network, by accessing the Top Charts view in NetCrunch network monitor (https://www.adremsoft.com/). Top Charts is a view in which you can set seve…

650 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question