SMTP 553 Error

I am receiving a bounce back from yahoo addresses when users try to email

I am using Exchange Server on WIndows SBS 2003.

Your message did not reach some or all of the intended recipients.

      Subject:      Testin email
      Sent:      1/23/2008 11:58 AM

The following recipient(s) could not be reached: on 1/25/2008 9:52 AM
            There was a SMTP communication problem with the recipient's email server.  Please contact your system administrator.
            < #5.5.0 smtp;553 Mail from not allowed - [10]>
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 DNS is a mess.

You have your MX records set incorrectly with a zero weight (change it from 0 to 10), there is no host that corresponds with the MX records (you need to create a host called and point it to your external IP address, and your SMTP greeting is malformed (but isn't going to work even if you fix it) it should be ->

The quickes solution here is to route all your mail via your smarthost - as you are clearly using the POP3 connector to receive mail, then you don't have much of a choice ->
tanya_andreasenAuthor Commented:
Ok, I looked under the smtp settings of my exchange server and everything appears normal.

My Hosting information ( has my mmx records set up. Everything looks good there as well.

Any more ideas?
>>Ok, I looked under the smtp settings of my exchange server and everything appears normal.

It is still wrong, change your SMTP greeting with the link I gave above to instead of just

Now that your A record exists (it didn't before - could be slow DNS propogation), I can test further.  Your DNS records are now all good.

Your reverse DNS is now incorrect, it is pointing to which then points to a different IP;

1.  Talk to your ISP and tell them you want a reverse DNS entry on your IP pointing at
2.  Fix your SMTP greeting

Then, you should be done
tanya_andreasenAuthor Commented:
Ok, everything is done, but I am still not able to send to yahoo accounts.
I have contacted my ISP and they changed it to point to
I have changed my smtp greeting to

Thank you for all of your help.


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.