In fact, many of the major email providers such as Gmail and Hotmail are starting to make full authentication almost a requirement.
But setting up authentication is confusing, and there is no easy way to get your authentication in order without generating server side keys, figuring out SPF record formats, making sure your DNS entries are correct, etc, etc.
It's a steep learning curve to say the least.
If you have any questions or get stock, feel free to Contact Us.
Until next time, here's to your new, improved inbox success :)