To configure a next hop server

1. On a computer that is running the Communicator Web Access snap-in, log on as a member of the local Administrators group and the RTCUniversalServerAdmins group.
   
   
2. Click Start, point to Administrative Tools, and then click Microsoft Office Communications Server 2007 R2, Communicator Web Access.
   
   
3. In the console pane, expand the name of the computer that hosts the virtual server for which you want to specify a next hop server, right-click the name of the virtual server, and then click Properties.
   
   
4. In the Propertiesdialog box, on the Next Hoptab, select a server or server pool from the Next hop pooldropdown.
   
   
5. Type the listening port of the server or server pool in the Portbox and then click OK.
   
   

   Note:
   Typically, Office Communications Server uses port 5061 as the listening port.