Coldfusion 7 - mail sending bad 'helo' - email

Question

I've got my own box sitting in a rack. It's Win2000 running CF 7 and using the rack company's smtp server. I can't send emails. When I try, they simply go to the undeliverable email folder. Support says my server is sending a non-verifiable helo message. So their smtp server wont send it.
It being CF 7, the admin has nowhere to specify U/P for auth. However I SHOULD be able to do that within the tag. When I do, I get no errors but the mail goes to the undeliverable folder.
CODE:
<cftry>
<cfmail to="jxxx#yahoo.com"
from="jxxx#xxx.com"
subject="xxx.com Sign-up"
server="smtp.xxx.net"
port="25"
username="valid-account#xxx.net"
password="password" >
This is a test - with server specified
</cfmail>
Success w/ server user defined
<cfcatch type="any">
<strong>ERROR: #cfcatch.Message#</strong><BR />
#cfcatch.Detail#
</cfcatch>
</cftry>
<cftry>
<cfmail to="jxxx#yahoo.com"
from="xxx#xxx.net"
subject="xxx.com Sign-up" >
This is a test - without server specified
</cfmail>
Success w/o server user defined
<cfcatch type="any">
<strong>ERROR: #cfcatch.Message#</strong><BR />
#cfcatch.Detail#
</cfcatch>
</cftry>
I don't know much about mail servers...
Any ideas?

Answer 1

This could be an issue with DNS and the inability of the receiving system to either do a reverse DNS lookup or maybe it isn't in DNS at all.
another possibility is that non-verifable Helo means that you don't have FQDN associated with the system (perhaps your system name does not have a domain associated with it?) (ie. helo me) probably going to be bounced versus "helo me.somewhere.com".
so - don't think this a CF issue from a coding perspective - something that is related to your system setting (FQDN perhaps) or DNS in your location. Most anti-spam / anti-open relay settings are going to look at DNS for some level of validation.