Solved

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

Posted on 2008-09-29
3
465 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
3 Comments
 
LVL 5

Expert Comment

by:MarcBorst
Comment Utility
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
Comment Utility
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
Comment Utility
This problem is known as Backscatter.

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

Featured Post

Enabling OSINT in Activity Based Intelligence

Activity based intelligence (ABI) requires access to all available sources of data. Recorded Future allows analysts to observe structured data on the open, deep, and dark web.

Join & Write a Comment

Following basic email etiquette rules will help you write a professional email and achieve a good, lasting impression with your contacts.
This article explains in simple steps how to renew expiring Exchange Server Internal Transport Certificate.
In this video we show how to create an Address List 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 Organization >> Ad…
In this video we show how to create an email address policy 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 Mail Flow…

743 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

Need Help in Real-Time?

Connect with top rated Experts

12 Experts available now in Live!

Get 1:1 Help Now