This problem has been popping up a number of places, so I figured I would look for a place to ask people, instead of trying to find articles on Google, and paying $15 for a solution that doesn't help...

We're trying to send mail to the inside of our exchenge server from the outside. We can read mail recieved, but we can't reply through the server. We were hoping to make it like it came from the inside, so the email you sent to someone@professionaladdress.com doesnt end up with a reply from somethingwithnumbers@somewhereelse.net. We don't have an SMTP address.

Any help provided will be better than nothing. Thanks for your time ^_^

Hello Prinny, and welcome to the PCHF!

Have you already a realworld DNS for your exchange server?

Say your company is called "John" your domain would be john.local and your realworld DNS would be johnshop.com

username@john.local would refer to internal users and emails, and username@johnshop.com would then point to username@john.local and direct it to the right mailbox store.