Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

Filter recipients who are not in the Directory

Posted on 2011-09-20
2
Medium Priority
?
294 Views
Last Modified: 2012-05-12
Hello,

I have this setting enabled "Filter recipients who are not in the Directory" in our Exchange Server 2003. However, our consulting company has advised to remove this setting to prevent hackers from farming for valid e-mail addresses. Any thoughts on this? Do you guys leave this setting on or off and why? Thanks!
0
Comment
Question by:vrosas_03
2 Comments
 
LVL 1

Accepted Solution

by:
TPAMisfit earned 2000 total points
ID: 36570672
I think Microsoft recommends not enabling this feature because once you do, a Directory Harvest Attack can be used to gain knowledge of the valid e-mail addresses in your organization. Personally, we have it enabled and use the Tar pit KB to help difuse any attacks.

See MS article:

After you enable recipient filtering, a certain technique may be used against your Exchange server to gather information about the valid e-mail addresses in your organization. This technique is known as a Directory Harvest Attack.

For more information about how to help prevent this kind of attack, click the following article number to view the article in the Microsoft Knowledge Base:
 842851  SMTP tar pit feature for Windows Server 2003
0
 

Author Closing Comment

by:vrosas_03
ID: 36594049
Thanks. I guess I'll have to remove on my end for security.

0

Featured Post

 The Evil-ution of Network Security Threats

What are the hacks that forever changed the security industry? To answer that question, we created an exciting new eBook that takes you on a trip through hacking history. It explores the top hacks from the 80s to 2010s, why they mattered, and how the security industry responded.

Question has a verified solution.

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

If you have come across a situation where you need to find some EDB mailbox recovery techniques, then here you will find the same. In this article, we will take you through three techniques using which you will be able to perform EDB recovery. You …
There can be many situations demanding the conversion of Outlook OST files to PST format and as such, there is no shortage of automated tools to perform this conversion. However, what makes Stellar OST to PST converter stand above the rest? Let us e…
Sending a Secure fax is easy with eFax Corporate (http://www.enterprise.efax.com). First, just open a new email message. In the To field, type your recipient's fax number @efaxsend.com. You can even send a secure international fax — just include t…
When cloud platforms entered the scene, users and companies jumped on board to take advantage of the many benefits, like the ability to work and connect with company information from various locations. What many didn't foresee was the increased risk…

783 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