We have an Exchange Server (2003, SP2) that is only accessible internally on the domain. I need help learning how to make it available to our users from the internet. The Exchange server is running Windows Server 2003 R2, and it is also a DNS and DC (despite the fact that Microsoft does not recommend this configuration). Blackberry Professional Software is installed, making it possible for BlackBerry users to access their e-mail, but the introduction of other phones, such as androids and iPads, will make it necessary to allow access to corporate e-mail via an internet URL.
Currently, the 15 domain users can get their e-mail internally with Outlook and OWA, but I want to make it available from the internet. Does this work through port-forwarding? We have a static IP for the network, on a Cisco ASA5505 firewall, if that helps. But I'm not sure how to set up IIS, if that is required. I do not have a front-end exchange server (and I don’t know what’s involved in setting this up, if it's required). Please help me figure out the parts that I'm missing to make this Exchange server available over the internet. You will probably require more information, so please let me know what else is needed.