w2k3 SMTP email problem: 550 Access denied - Invalid HELO name

Can someone please walk me through this configuration problem? We have a w2k3 server in a data center that is sending out automated emails (from the same @ourdomain.com address as our corporate Exchange 2003 Server). For the most part, we aren't having any issues except for some recipients are bouncing the emails back with a "550 Access denied - Invalid HELO name" error.

I just don't know the proper configuration settings on the virtual SMTP to prevent this from happening. I assume this is what prevents email spoofing, so there is likely something I need to set (and perhaps grant permission on from our Exchange Server?)

Help.. I am lost.

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Forget about what your Exchange server has, that is irrelevant.

The server in the data centre needs a valid host name pointing to it.

So that could be host.example.net.
Then you need to set in the reverse DNS records (aka PTR records) host.example.net on that server external IP address. You may have a control panel to do that, the company that is providing the connectivity in the data centre may have to do it for you.

Then you set the FQDN to host.example.net - changing it from servername. It is the servername that is causing the initial error, and lack of DNS and reverse DNS will also be causing you email delivery issues. So I am actually covering more than you need.

In SMTP Config in IIS manager, right click on the Default SMTP VS and choose Properties. Click on the tab Delivery, then Advanced. In the FQDN change the name to match your reverse DNS and IP address entry. That should not be the same as your Exchange server, it should have its own DNS information.

dbrenneckeAuthor Commented:
I get the jist of what needs to be done.. but for clarifty...

Exchange IP: which resoves to
"mail.mycompany.com"  with a
Top-level Domain of "mycompany.com"

Data Center IP: which resolves to
"" with a
Top Level Domain of "ltdomains.com"

The Advnaced Delivery setting is:
FQDN: MyMachineName

So I need a bit more help getting this right (sorry to be such a newbie)!

dbrenneckeAuthor Commented:
Makes sense... I will get with the data center and see what they can assist with. Thanks for the thorough response.
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