Glad I could be of help.

I use my auto responder heavily for my visitors who request information. I was trying a windows based one for a long time from my home PC and was wondering why my results were so poor. Then when I decided to run everything on my web server with Auto Response Plus and set up the SPF's, the responses went to the moon. It was almost like all of the emails that were being sent through my ISP at home were going to nowhere. I was losing a ton of business from it.

Auto Response Plus is not much of a picnic to set up. You need to have forwarding addresses to handle undeliverables and stuff.

It doesn't matter if I was using an auto responder or not. Whatever the case may be, whatever mail server is sending an email to someone, the domain name I put at the end of the email address needs an SPF record with the IP address of the mail server permitted to send the email.

Look at the links in my previous post for more information on SPF.