Exchange 2010: Sending issues

Posted on 2011-02-28
Last Modified: 2012-05-11
This mornign a user tried to send an email to a customer and received the following error response: refected your message to the following e-mail addresses:

Customer Name ( gave this error:
<>... Domain of sender does not exist

Your message couldn't be delivered because you weren't recognized as a valid sender. Make sure your sending address is set up correctly and try to send the message again. If the problem continues, please contact your helpdesk.

Is this a problem on our end?  We just migrated to this server over two weeks ago, but this is the first time we have had a problem sending outside of our domain.
Question by:VoodooFrog
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
  • 5
  • 3
  • 2
  • +1
LVL 76

Expert Comment

by:Alan Hardisty
ID: 34997256
Please check that your server is RFC compliant and that it is configured correctly.  My article should help you:

With Exchange 2010 - check the SEND Connector FQDN and make sure that is displays a resolvable address in DNS externally and that this FQDN resolves back to your server's sending IP Address.
LVL 10

Expert Comment

by:Muzafar Momin
ID: 34997281
please check your MX and PTR
LVL 11

Expert Comment

ID: 34997453
Can you please confirm that you have a SPF-record defined for your domain.
I've come across this error before when no rDNS record nor SPF could be found for your domain.

Because of that, the recipient's spam-filter cannot verify that your server's IP-address is allowed to send mails for your domain.

Furthermore, make sure that the FQDN on the Send connector is filled in correctly.

Kind regards,

Is Your AD Toolbox Looking More Like a Toybox?

Managing Active Directory can get complicated.  Often, the native tools for managing AD are just not up to the task.  The largest Active Directory installations in the world have relied on one tool to manage their day-to-day administration tasks: Hyena. Start your trial today.


Author Comment

ID: 35000166
Alright, I think this may be the SPF record.

Now, I am a little concerned how the dns is set up.  Our mail server has the FQDN send connector of  

-The domain is hosted offsite.  
-The DNS record for has a an MX record of resolves to our Exchange server's external IP Address.
-I have changed the SPF on the DNS for to allow sending from and the IP Address of has a DNS A record, but no SPF, MX, PTR, NS, or SOA records.

For the reverse lookup tests, do I put in the domain name or the IP address?

Let me know if I need to make changes to anything.

LVL 11

Accepted Solution

MichaelVH earned 250 total points
ID: 35000235

the way you put it there, it seems to be quite okay :)

However; I'm not clear what you refer to with "For the reverse lookup tests, do I put in the domain name or the IP address?"; what do you mean?

LVL 76

Expert Comment

by:Alan Hardisty
ID: 35000274
You can use nslookup for reverse DNS:

In a command prompt type the following:


nslookup your-fixed-ip-address

The first check should return your IP address, the second should return mail.domain.con
LVL 76

Expert Comment

by:Alan Hardisty
ID: 35000287
You can also use the following site to check and test your SPF record:

Author Comment

ID: 35000347
MichaelVH, I was asking because when I put in the fixed external IP into a reverse lookup I am not getting

nslookup returns the fixed IP appropriately.

nslookup fixed-ip-address returns a domain name that I assume our ISP uses to identify our IP address, not as I would expect.

LVL 76

Assisted Solution

by:Alan Hardisty
Alan Hardisty earned 250 total points
ID: 35000383
Okay - so your Reverse DNS is not configured properly and you will need to call your ISP and get them to configure Reverse DNS as to match your FQDN on your SEND connector.

Author Comment

ID: 35000995
OK, I am working on getting the reverse lookup fixed.

In the meanwhile, does there need to be an SPF record for
LVL 76

Expert Comment

by:Alan Hardisty
ID: 35001044
You don't NEED an SPF record - it is better to not have one than to have an incorrect one, but it can be good to reduce spam and to help tell the world the mail servers that are authorised to send mail on behalf of your domain.

Featured Post

Edgartown IT Case Study

Learn about Edgartown's quest to ensure the safety and security of the entire town's employee and citizen data. Read the case study!

Question has a verified solution.

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

Lotus Notes – formerly IBM Notes – is an email client application, while IBM Domino (earlier Lotus Domino) is an email server. The client possesses a set of features that are even more advanced as compared to that of Outlook. Likewise, IBM Domino is…
In-place Upgrading Dirsync to Azure AD Connect
In this Micro Video tutorial you will learn the basics about Database Availability Groups and How to configure one using a live Exchange Server Environment. The video tutorial explains the basics of the Exchange server Database Availability grou…
This video demonstrates how to sync Microsoft Exchange Public Folders with smartphones using CodeTwo Exchange Sync and Exchange ActiveSync. To learn more about CodeTwo Exchange Sync and download the free trial, go to:…

732 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