Hi Jason,
A little more information would be very helpfull in answering your question. I´m not quite sure what is in the inside and what is on the outside of your firewall? Are there translations involved? Did IP adresses of their local machines changed when you put them behind the firewall? Or is the IP of the sql server changed (from their point of view?).
Please provide more information on what you want to achieve, and what you tried so far. I´m sure we can help you out then.
Kind regards,
Leo