Newly created Virtual Services on a LoadMaster are set Transparent on a LoadMaster by default. In Transparent mode, the LoadMaster will forward traffic towards the Lync External EDGE Server while retaining the source IP address with which it arrived at the LoadMaster.

For L7 transparency for Lync External EDGE Servers to work properly:

a) The Real Server settings must ensure that all server replies to client requests are routed through the LoadMaster. Typically, this is achieved by making the LoadMaster the Real Server's default gateway.

b) No clients may be located in the same IP subnet with the Real Servers. If necessary, you can use additional ports on the LoadMaster to ensure that Real Servers and Clients are located on distinct IP subnets.