Solved

Thousands of "Undelivered Mail Returned to Sender" messages everyday from mail I did not send!

Posted on 2008-09-29
3
474 Views
Last Modified: 2013-11-30
I'm running Exchange 2003 on W2k3 server. Lately, I'm getting literally thousands of returned mail messages daily as if someone is sending mail from my domain to huge lists and I'm getting all of the returned mail.  Is there anyway to tell whats going on here?

I started digging around in my Exchange System Manager and found a bunch of unknown domain names in my outbound SMTP connections.  I frooze all of them besides my domains.  How can I stop this?!?!
0
Comment
Question by:MFredin
[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
3 Comments
 
LVL 5

Expert Comment

by:MarcBorst
ID: 22597457
Someone is faking your email-address. Of course, the undeliverable report returns to the correct address. First of all please check, if your server is an open smtp-relay. Please post the settings of the follwing here.

System Manager > Administrative Groups > First Administrative Group > Servername > Protocols > SMTP > Virtual Standard Server for SMTP > Properties > Tab "Access" > Relay.

Maybe Relaying is allowed for everyone. If you search the internet about "testing open smtp relay" you will also find some websites, where you can do that.
0
 

Author Comment

by:MFredin
ID: 22597651
Under relay I have "Select which computers may relay through this virtual server: ONLY THE LIST BELOW"  and I dont have any computers in the list.  I also have "Allow all computers which successfully authenticate to relay, regardless of the list above" CHECKED.

I did a few relay tests and I am NOT an open SMTP relay.
0
 
LVL 31

Accepted Solution

by:
moorhouselondon earned 500 total points
ID: 22598170
This problem is known as Backscatter.

http://spamlinks.net/prevent-secure-backscatter.htm
0

Featured Post

Has Powershell sent you back into the Stone Age?

If managing Active Directory using Windows Powershell® is making you feel like you stepped back in time, you are not alone.  For nearly 20 years, AD admins around the world have used one tool for day-to-day AD management: Hyena. Discover why.

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.
When you’re making plans to join the modern business race, you should analyze various details that may affect your results. Nowadays, millions of businesses are trying to grow into established and appreciated professional enterprises.
This video shows how to quickly and easily add an email signature for all users on Exchange 2016. The resulting signature is applied on a server level by Exchange Online. The email signature template has been downloaded from: www.mail-signatures…
Exchange organizations may use the Journaling Agent of the Transport Service to archive messages going through Exchange. However, if the Transport Service is integrated with some email content management application (such as an antispam), the admini…

763 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