Okay I'm able to send out emails now using TLS and using something along the lines of:
sendmail -f "firstname.lastname@example.org" email@example.com
But... I still can't seem to send mail from firstname.lastname@example.org
How can I make it so that I send emails from the right domain without having to send it from my username? This is kind of AT&T specific I guess, but before I started sending out emails with that "from" address, I was getting error 553 relaying denied from AT&T servers.
Is there a way to fudge the servers where I can send out a from address that doesn't get denied that's from my own domain?