Solved

Outlook Flooded with Undeliverable Emails

Posted on 2015-02-10
4
16 Views
Last Modified: 2016-06-03
Have a real strange problem here folks...

Environment is SBS 2010 with WIN7 clients, running Office 2010. There are 8 people in this environment and they all seem fine but one person who keeps getting undeliverable bounce backs on his outlook client, they all seem to come from the same domain, always with a barracuda error message. Here's the trick however, I have tested and re-tested their domain against blacklists and they are clean as a whistle, send an Email to myself on both my hotmail account and my exchange account (hosted on the cloud by intermedia) and they came through just fine. So it almost looks like outlook is just generating these bounce backs without even trying to send the Emails? Very strange...
0
Comment
Question by:Marvio_Santos
[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
  • 2
4 Comments
 
LVL 31

Expert Comment

by:Gareth Gudger
ID: 40601556
I assume this means the user actually send to this domain originally and is getting rejected? If so, can you post the NDR here?

If they never sent to this domain this is likely just a backscatter attack. More info on a backscatter attack here. If it is, not much you can do except get a really good message-hygiene solution that can protect against this, or, blacklist that domain.
http://en.wikipedia.org/wiki/Backscatter_(email)
0
 
LVL 1

Accepted Solution

by:
Marvio_Santos earned 0 total points
ID: 40601646
I finally figured it out... They did have a virus infection a while back, but exchange was still trying to send the Emails from back when, cleared out all the queues and it was fine
0
 
LVL 31

Expert Comment

by:Gareth Gudger
ID: 40601732
Glad you got it going. That must have sent out thousands of emails to still be processing, even now. Did you get blacklisted?
0

Featured Post

Secure Your WordPress Site: 5 Essential Approaches

WordPress is the web's most popular CMS, but its dominance also makes it a target for attackers. Our eBook will show you how to:

Prevent costly exploits of core and plugin vulnerabilities
Repel automated attacks
Lock down your dashboard, secure your code, and protect your users

Question has a verified solution.

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

This article aims to explain the working of CircularLogArchiver. This tool was designed to solve the buildup of log file in cases where systems do not support circular logging or where circular logging is not enabled
When you have clients or friends from around the world, it becomes a challenge to arrange a meeting or effectively manage your time. This is where Outlook's capability to show 2 time zones in one calendar comes in handy.
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
This video discusses moving either the default database or any database to a new volume.

710 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