Error message when send email

When I send an email to certain email address I get the following error message in  a reply message...

There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.
  <Server #5.5.0 smtp;553-mail rejected because your IP is in DUL. See>

What is the problem here?

Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

> your IP is in DUL

The reverse DNS of your server shows that your server is "in DUL" - "in Dial-Up Land".  Most likely you are using a DSL connection or some other form of connection which could be construed as a home-user-access-dial-up equivalent.

To get around this problem you could add another SMTP Connector which uses the address space of the rejecting domains & forwards the e-mails to your own ISPs SMTP relay servers instead.  Alternatively, you could send all your e-mail through your own ISP's relay servers.
dwelldonAuthor Commented:
I am going through a cable modem, not sure about setting up SMTP connectors have you any instructions?
Right-click your Connectors folder in the Exchange System Manager and choose New->SMTP Connector.  On the General tab, enter the relay server at your ISP in the Forward [...] box (check the radio dial to enable it).  Under the Address Space tab, add in an SMTP type for each of the destinations required with a cost of 1.  Click OK when done & edit the pre-existing SMTP Connector & on it's Address Space tab, edit the * entry and change the cost to 25.  The new connector will then take precedence over the old one but will only deliver mail destined for those specific locations.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.