Solved

Email being blocked

Posted on 2011-03-25
9
203 Views
Last Modified: 2012-05-11
I have a very unusual email issue.  I have users who are sending emails to multiple domains but the recipients are saying they are not getting them.  The mail server logs are saying the email is being delivered to the destination servers.  In addition to this weirdness, I have one user who sends an email from his outlook client to a certain email address and gets an immediate bounceback with a denied message.  But, if he sends it from OWA, it gets delivered to the destination mail server.
I have checked all blacklists.  I have conected destination mail server administrators and we are not on internal blacklists, from what I can tell.  

Now, they did have an email virus on the network last week that sent out several emails.  But it was cleaned.
I am thinking that the virus may have marked the sending folks emails as spam on the clients.
Any thoughts ideas or ideas would help.  
0
Comment
Question by:itarrows
  • 5
  • 3
9 Comments
 
LVL 7

Expert Comment

by:mmicha
Comment Utility
Are you natively sending mail through Exchange?  Possibly using a smarthost or outbound scanning?  Maybe something outside of Exchange blocking.  Spam Filter on your end (outbound) or filter on the other side of the fence.  

Is it only to certain domains?
0
 

Author Comment

by:itarrows
Comment Utility
We were using Exchange Defender as a smart host.  But, I am now sending directly out of exchange for outbound and by-passing the smarthost.  Also, the SMTP logs say it is being delivered to the destination mail server successfully.
0
 
LVL 7

Expert Comment

by:mmicha
Comment Utility
It's only to specific domains?  If you tested email flow to say hotmail or something it would work fine?

I'm thinking if Exchange says the mail is getting through it completely and leaving out the send connector is a foreign thing causing issue.

Does the deny message include any header information that may give clues?
0
 
LVL 37

Expert Comment

by:Neil Russell
Comment Utility
Have you enabled verobose SMTP logging so that you can see a full transaction conversation with a remote server connection?

IF You get an imeadiate bounce in Outlook client, do a few things.....
firstly delete the useres .NK2 file

Second make sure that the user has NO contact record for the user he is trying tosend too in ANY address book.
0
What Is Threat Intelligence?

Threat intelligence is often discussed, but rarely understood. Starting with a precise definition, along with clear business goals, is essential.

 

Author Comment

by:itarrows
Comment Utility
Neilsr, that's a good idea.  Let me look into that.
0
 

Author Comment

by:itarrows
Comment Utility
Has anyone heard of fingerprinting emails with neetwork solutions.
0
 
LVL 7

Expert Comment

by:mmicha
Comment Utility
I've not heard of it...  Is that what you think is causing the bouncing and non delivery?
0
 

Accepted Solution

by:
itarrows earned 0 total points
Comment Utility
The issue was that, certain domains had us marked as sending SPAM, which we had a virus last week, but had cleaned it.  But, the receiving domains (mostly hosted with mxlogic.com) had us flagged, if emails came in with a certain signature tied to it.  This is why emails witthout a signature, went through fine, but emails with the signature got dumped at the receiving site.  We had to contact them and ask them to remove the flag.
0
 

Author Closing Comment

by:itarrows
Comment Utility
I found this out working with network solutions and their new way to fight SPAM.
0

Featured Post

Promote certifications in your email signature

Has your company recently won an award or achieved a certification? They'll no doubt want to show it off. Email signature images used to promote certifications & awards can instantly establish credibility with a recipient and provide you with numerous benefits.

Join & Write a Comment

"Migrate" an SMTP relay receive connector to a new server using info from an old server.
Find out how to use Active Directory data for email signature management in Microsoft Exchange and Office 365.
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…

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

Need Help in Real-Time?

Connect with top rated Experts

5 Experts available now in Live!

Get 1:1 Help Now