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SMTP Validation


Cant find this in any of the other posts. We are getting bounces due to Reverse DNS errors because our server is natted behind the firewall. Here is more info:
#5.5.0 smtp;553 recipient does not accept connections from IP Addresses which have no reverse-DNS (PTR record) assigned.> #SMTP#
Original message headers:
Received: from MYCOMPANY.lan ([]) by
server01.MYCOMPANY.lan with
Microsoft SMTPSVC(6.0.3790.3959); Fri, 7 Dec 2007 14:32:00 -0700
Date: Fri, 7 Dec 2007 14:32:00 -0700

Any suggestions?


Are you setup to send email via SMTP or via php mail? If you’re using php mail try switching to SMTP and see if that helps it (assuming your SMTP server is on your domain).


I am set to send through SMTP and not only is the SMTP server on the same domain its on the same server as helpspot.


Can you send an email to customer.service at so I can take a look at the headers your installation is sending and see what might be adjusted. Thanks.

Note, I might not be able to check this until tomorrow.


I will send this to you right away, i understand about time frame.


This issue is resolved and in the end we went to the hosted solution to solve this issue. Sadly I have another for which I will open a new thread, but I wanted to Thank you for your help on this one.