I just had to create an Inbound Rule recently:
On the Windows 2008 Server, on the Administrative Tools menu, select Windows Firewall with Advanced Security console.
In the left pane of the console, select Inbound Rules.
Right-click, and select New Rule.
Select Specific Port.
Select 10000 or the actual port number for Sage MAS 200.
Select Allow Connection.
Click the Profile tab, and select Domain, Private, Public.
Name the new rule MAS200 or a name of your choice.