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SBS 2003 clients cannot send email to us getting open relay error

We have a sbs 2003 box and are hosting exchange.  For the past week when some of our clients email us they get a bounce back that says:
Your message could not be delivered.

The recipient's computer rejected your e-mail.
Please verify the recipient's e-mail address and resend.

    Recipient: <email address>
    Reason:    5.7.1 ip address has been blocked by Open Relay Test

When i open the attached doc it says:
Reporting-MTA: dns; priv-edmwes04.telusplanet.net
Arrival-Date: Sun, 10 Jul 2011 21:32:52 -0600
Received-From-MTA: dns; edmwcm03 (ip address)

Final-Recipient: RFC822; <email>
Action: failed
Status: 5.1.1
Remote-MTA: dns; mail.rejtool.com (
Diagnostic-Code: smtp; 550 5.7.1 ip address has been blocked by Open Relay Test

is this an issue with our server or the senders?


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8/22/2022 - Mon

ip address has been blocked by Open Relay Test

you are using a smarthost i presume to deiliver mail, and your server's IP has been blocked for some reason , possibly spam. try to use direct MX delivery instead

It would seem from your description that the problem is with some of the people sending email to your organization.  

Mail servers can be set up to not *accept* mail from servers that they think are open relays, but I don't think they care when *delivering* mail.

Anyway, to test if your server is indeed an open relay, go to mxtoolbox.com, and use the Diagnostics tab.


It is not our server being blocked, it is clients trying to email us.  They have not had issues before.
I have checked us on MXToolbox and we are not an open relay or blacklisted.
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I did a bunch of windows updates on the SBS 2003 server and rebooted.  Everything started working until today, same issue.  So I rebooted again, however this time the one user is still getting these bounce backs.  I have confirmed by sending the user one from my personal email address that always goes through and received the same error message:

Your message could not be delivered.
The recipient's computer rejected your email.
Please verify the recipient's email address and resend.

Recipient: (users email address)
Reason: 5.7.1 (iP address) has been blocked by open relay test.

I actually added this user on an email to another user at same domain and one went through and this one failed.

I think I'm not getting it.

Is this user part of your email domain, and emails to this user (from outside of your domain) get bounced back?

Or is this someone you are trying to send mail to?

This is an error that bounces back to the user sending it to our domain.  I have tested it with another of my email addresses and I get the same error.  The smtp server I am using is smtp.telus.net, this resolves to an ip address that is on blacklists.

But there are alot of telus users that use this smtp server.

I am just wondering why our server just started dis-allowing these emails from clients who used to email us fine.
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This shouldn't be your problem.  It should be up to the email administrator of the sender's domain to fix it.  It is his/her job to see to it that their users can send mail (just like if someone in your organization cannot send mail to someone, you will get a call from the user who cannot send mail)

What kind of filtering are you doing on your side?  Do you use any kind of Block lists?  Look at the configuration of IMF (Intelligent Message Filtering) on your server.


Was only part of the problem.  Had a few limits placed on accounts as well.