?
Solved

Outbound spam issue

Posted on 2010-11-22
1
Medium Priority
?
469 Views
Last Modified: 2012-05-10
After hours, the mail server is being hit with thousands of outbound spam messages coming from postmaster@domain.  Postmaster does not exist.  It's reaking havoc on our network, causing us to be blacklisted etc.  I have scanned every pc, checked for open relay, firewall is configured for all outbound smtp traffic to go thru mail server.  No matter what, mail keeps flooding network, usually after 5pm and on weekends.  
0
Comment
Question by:szagoria
[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
1 Comment
 
LVL 76

Accepted Solution

by:
Alan Hardisty earned 2000 total points
ID: 34191091
You are probably on the receiving end of an NDR attack.

Please have a read of my Article that should help you resolve this problem by enabling Recipient Filtering:

http://www.experts-exchange.com/Software/Server_Software/Email_Servers/Exchange/A_2556-Why-are-my-outbound-queues-filling-up-with-mail-I-didn't-send.html
0

Featured Post

Office 365 Training for IT Pros

Learn how to provision tenants, synchronize on-premise Active Directory, implement Single Sign-On, customize Office deployment, and protect your organization with eDiscovery and DLP policies.  Only from Platform Scholar.

Question has a verified solution.

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

This article explains how to install and use the NTBackup utility that comes with Windows Server.
This article provides a convenient collection of links to Microsoft provided Security Patches for operating systems that have reached their End of Life support cycle. Included operating systems covered by this article are Windows XP,  Windows Server…
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…
A short tutorial showing how to set up an email signature in Outlook on the Web (previously known as OWA). For free email signatures designs, visit https://www.mail-signatures.com/articles/signature-templates/?sts=6651 If you want to manage em…
Suggested Courses

762 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