Microsoft® Lync® Server 2013 Unleashed Second Edition

Optimized External Access Path

Another strong benefit of using a Director is its capability to serve as a barrier between internal pools and external traffic. To understand the benefit here, it is important to know that Edge servers do not authenticate external user requests across the Internet and merely pass this traffic to a next-hop internal server to handle authentication. This means that without a Director all external traffic is being authenticated by a Front End pool, or in other words, anonymous Internet traffic is being allowed to communicate with an internal domain member server.

Instead of allowing authentication requests from an Edge server to pass directly to a Front End pool, a Director can be placed in between this communication ...