Just to be clear, you don't need to hook your fax server(s) to the Unity box at all... you need to have a gateway installed onto one of the Exchange servers in your site (which can be the Unity server, of course) and those fax server(s) need to then be configured to use that gateway to route faxes into users' mailboxes and respond to outbound fax requests.
Unity doesn't get faxes directly from any fax server... the faxes are routed directly to mail users' mailboxes by the fax gateway itself. Outbound requests go through the gateway as well. We route oubound faxes to the "FAX" address and Exchange takes care of finding the server that has the gateway on it and getting the message to that box such that it can be handled by the gateway. Very clean.
Just about all fax servers work in this mannor, including LightningFax (which is what I'm assuming you're using).
The multiple fax server setup isn't a supported ActiveFax configuration but you're free to do this as a third party fax config no problem. The Lightning docuemntation (or whatever fax server you're using) will have info on how to attach multiple fax servers to the same gateway. There are usually weighted least cost routing type rules you can setup in this config to determine which fax server responds to outbound fax requests first and the like... this way you can set one up to handle just incoming and one is responsible for all outgoing.
Jeff Lindborg
Unity Product Architect
Active Voice
jlindborg@activevoice.com
http://members.home.net/jlindborg
