We help IT Professionals succeed at work.

External mail not being delivered to certain domains.

Last Modified: 2013-11-22
We currently have three exchange 2003 servers in a cluster two of them have a smart host to one exchange server that handles all mail outbound and in bound.  i.e. server1 server2 smarthosted to server3  which handles all inbound and outbound traffic. The issue is some external mail is being delivered to certain domains such as gmail,msn,hotmail, and others but its not being delivered to aol,comcast.net, other others.
It has been working fine just recently started to happen. I have check to see if we our i.p. has been blacklisted and it has not. i can telnet to these domains that are not receiving our messages. i have check out reverse dns lookup check out fine.
All servers are behind a barracuda 400 spam firewall but it does not check outbound mail.

Thank you in advanced.
Watch Question

Is the email actually leaving your servers or is it sitting on the exchange servers waiting for delivery?


It is sitting in our server waiting for delivery

Is there a reason for the failed delivery?  Unable to connect etc etc


Users will get this
This is an automatically generated Delivery Status Notification.



Delivery to the following recipients has been delayed.

And when i track it it says this

Message Routed and Queued for Remote Delivery

OK, sorry for the list of questions but this sound similar to an issue I had a while back.

We were sending mail via CRM, turned out AOL were blocking mail, due to the CRM ID in the subject header, and the quantity we were sending.  In the end I had to speak to AOL and get them to "white list" us.  

When I checked we were not on any blacklist.  Not sure if this helps, but I would suggest you speak to AOL and take it from there
This one is on us!
(Get your first solution completely free - no credit card required)


well now it seems like aol is working fine but places like yahoo and comcast are now being que.... any other suggestions .

Gain unlimited access to on-demand training courses with an Experts Exchange subscription.

Get Access
Why Experts Exchange?

Experts Exchange always has the answer, or at the least points me in the correct direction! It is like having another employee that is extremely experienced.

Jim Murphy
Programmer at Smart IT Solutions

When asked, what has been your best career decision?

Deciding to stick with EE.

Mohamed Asif
Technical Department Head

Being involved with EE helped me to grow personally and professionally.

Carl Webster
CTP, Sr Infrastructure Consultant
Empower Your Career
Did You Know?

We've partnered with two important charities to provide clean water and computer science education to those who need it most. READ MORE

Ask ANY Question

Connect with Certified Experts to gain insight and support on specific technology challenges including:

  • Troubleshooting
  • Research
  • Professional Opinions
Unlock the solution to this question.
Join our community and discover your potential

Experts Exchange is the only place where you can interact directly with leading experts in the technology field. Become a member today and access the collective knowledge of thousands of technology experts.

*This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.


Please enter a first name

Please enter a last name

8+ characters (letters, numbers, and a symbol)

By clicking, you agree to the Terms of Use and Privacy Policy.