Windows Server 2008 can be used as a multicast router between IPv4 networks. It requires to install and configure Routing and Remote Access service.
There are two IP networks 192.168.10.0 and 192.168.20.0 connected through a computer that has two network interfaces 192.168.10.3 and 192.168.20.1 installed and running under Windows Server 2008 (below this computer is called "router").
Network interfaces of the router should be configured as shown on screenshots below.
To configure routing
It is neccessary to wait for short time interval until the router locates all network nodes that use multicast UDP protocol.
On the pictures below you can see TCP/IP protocol settings of computers and "Network settings" of Vypress Chat from different network segments. It is important to specify a default gateway for each computer in subnetworks.
Open IGMP Group Table dialog to check that all network interfaces are found by the router and multicast group 18.104.22.168 is added successfully.
After short time interval (less than 5 minutes) since the configuring finished all Vypress Chat users should have seen each other in contact lists.