Solved

Stop Exchange 2003 from sending "unknown user" emails..

Posted on 2004-08-04
3
2,212 Views
Last Modified: 2008-01-16

Like everyone else on the planet, my server gets spammed to oblivion... however, my SBS2003 insists on sending messages back to the spammers with "unknown user" - and a copy of the SPAM!!

I'd much rather silently drop these messages - how do I do that?

also, I guess, is there a good alternative to Spam assassin for Exchange 2k3?
0
Comment
Question by:WintermuteCL
3 Comments
 
LVL 9

Accepted Solution

by:
robinluo earned 125 total points
ID: 11719603
ESM > Global Settings > Internet Message Format > (right pane) Default > Right click > Properties > Advanced tab > uncheck "Allow non-delivery report"
0
 
LVL 21

Assisted Solution

by:marc_nivens
marc_nivens earned 125 total points
ID: 11719655
You're getting hit with what we call NDR spam.  Spammers can use it to tell which addresses are valid and which ones are not.  The only way to do this natively is to turn off non-delivery reports.  If you choose to do this, follow these steps:

1.  Launch Exchange System Manager
2.  Expand Global Settings
3.  Click on Internet Message Formats
4.  Open properies on the * entry to the right
5.  Go to the advanced tab, uncheck allow non-delivery reports.

Note that this will stop all NDR's.  The more long term method of dealing with this is to use spam software.
0
 
LVL 2

Expert Comment

by:TomBoland
ID: 11953990
As far as the spam issue is concerned, I dropped SpamAssasin and now go with an external third-party spam service. I use Postini, but there are others out there. It costs about $3.00 per month per Exchange mailbox - not per SMTP address. Scans for virus, too. Keeps 80% of all emails off my servers completely. Junk mail is veiwable through web interface by user. We have been very happy with the False Positive rate. Pretty darn low.

In my example, what happens is that I had to change my MX record to point to Postini's servers and Postini then forwards the mail to me after it scans it. I also use them for outbound mail, so that my Exchange server is not published anywhere. My outbound mail has Postini's IP address on it.

You can lock down your firewall and Exchange server to accept SMTP traffic only from your third-party vendor.

This really limits your exposure to becoming a relay of any sort. Nobody gets to your Exchange server except through the third party spam filtering company.

I would never go back to SpamAssasin (which I actaully like) or client-based spam filtering again.

0

Featured Post

Optimizing Cloud Backup for Low Bandwidth

With cloud storage prices going down a growing number of SMBs start to use it for backup storage. Unfortunately, business data volume rarely fits the average Internet speed. This article provides an overview of main Internet speed challenges and reveals backup best practices.

Question has a verified solution.

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

We are happy to announce a brand new addition to our line of acclaimed email signature management products – CodeTwo Email Signatures for Office 365.
This article lists the top 5 free OST to PST Converter Tools. These tools save a lot of time for users when they want to convert OST to PST after their exchange server is no longer available or some other critical issue with exchange server or impor…
In this video we show how to create a Contact in Exchange 2013. We show this process by using the Exchange Admin Center. Log into Exchange Admin Center.: First we need to log into the Exchange Admin Center. Navigate to the Recipients >> Contact ta…
The video tutorial explains the basics of the Exchange server Database Availability groups. The components of this video include: 1. Automatic Failover 2. Failover Clustering 3. Active Manager

820 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