To this date, I still see a lot of confusion as to the IP requirements of Lync 2010 Edge Servers. I have seen the following questions:

  • Why do we require Public IP addresses on all 3 Lync Edge Roles when using Hardware Load Balancing?
  • Why does the Audio/Video Edge Role need a Public IP when behind a Hardware Load Balancer?
  • Why can we NAT when we’re doing DNS Load Balancing?
  • Why can’t we have a mix of Public IP and NAT’d IPs on the same Edge Server?

Have you been pondering the answer to any of the above four questions? If so, this blog article is for you. Read on…

Edge IP Requirements and Assumptions

First of all, let’s list out Edge Networking requirements and assumptions according to the official Lync 2010 documentation (only listing the ones relevant to this document to preface my own points):

  • Two network interface cards (NICs) configured as follows:
    • Edge internal interface is on a different network than the Edge external interface.
    • The Edge external interface NIC has three IP addresses bound to it (that is, Access, Web Conferencing and A/V, with the Access IP address set to primary and the other two IP addresses set to secondary).
    • Only one default gateway is configured and it is assigned to the Access Edge external interface and pointed to the external firewall’s IP address.  

--> La suite est à lire sur le site : http://www.shudnow.net/2012/04/25/lync-2010-edge-servers-and-ip-requirements-nat-vs-public-ip/