This one is stumping the techs..

I have a Win 7 machine with Win SBS 2011 in my office and an iMac. The Win machine is being setup for Exchange 2010.
My problem is this: I can't Remote Desktop in from my iMac into the Win machine, but CAN when outside the network.

The Win7 machine has a static IP, the iMac a dynamic. When I access the internal part of my router I can only see my iMac. I get a "can't connect to win-based machine" error when I try to Remote Connect.

The only thing I can think is that using the same gateway is somehow messing things up? I've had two techs try to figure this out and they're both stumped.

I was maybe thinking that since both comps are going out the same gateway that I should try anc configure the iMac to try and RDC on a different port, since maybe the iMac is listening on 3389 and sending the RDC back to itself?

Any help is appreciated, we're stumped on this one.

I was just told by my ISP support techs that they don't support help with this sort of thing and I'm on my own. Thaaaats fantastic.

-All drivers, anti-virus up-to-date
-subnet masks are the same I believe
-windows firewall is off
-the win 7 machine is actually the server, as it has SBS 2011 standard on it.

From the Imac, when logged into the router, I can't "see" the Server computer. It must not go through the router for the internet. It has a static IP.

I just tried for the past hour to connect to it using the the Static IP address in the "computer name" field but no luck. I just got home and it connects perfectly when entering the server computer's static IP

Apologies in advance if I'm explaining things wrong, I'm learning all of this stuff on the fly.