Exchange 2003 Setup

[ka1n]

Here is the situation: Our Exchange Server 2003 is setup so that internal mail can be sent via exchange and external email is sent through an external server so that email isn't denied by the recipient. For incoming mail, we use GFI's Pop2Exchange to download our email and the exchange server distributes the emails. We want to remove GFI altogether and just have our exchange handle all of our incoming emails. The Exchange Server is sitting behind a firewall. Any suggestions as to how to approach this matter would be greatly appreciated. Thanks