I'm sure this has been asked before, but for the life of me I can't find a question that covers exactly what I'm asking.
I've got a client who hosts their own domain. Godaddy's nameservers have all the A, CNAME, etc records and they point to my client's IP address (their ISP is SureWest in Kansas City).
However, my client's email is hosted on Gmail (Google Apps For Your Domain is what it used to be called I think). So, when any of their employees gets email, they go through the Gmail interface to read and to send.
However, they have an application (that I wrote so I have control over this) that sends emails on behalf of the system. This app can send quite a few emails (up to a couple thousand a day), to all different email addresses. These aren't unsolicited emails, and every one is unique.
I've currently got the app sending the email out through Microsoft SMTP Server since it's already installed and free. It seems to be working great (yeah, I had to do some obscure, to me, configuration with the SMTP server to get these emails to go out.)
Well, I think it's all working pretty well, but I have heard that you can do some other things like adding some sort of DNS entries to let receiving mail servers know that a certain ip address (in this case the external IP provided by SureWest) is allowed to send email on behalf of a domain.
Am I crazy? Does anyone know what I'm talking about? Are there any tutorials out there that can help me with this?