Skype for Business – Director Pool in DMZ (Secure Environment)
I was recently working for a customer where their security policy prohibited traffic from the internet terminating on servers within the LAN. Skype for Business (Including previous versions Lync and OCS) uses a Reverse Proxy to terminate web requests within the DMZ and re-write the requests to the Front End Pool(s) within the LAN. The request is received on TCP/443 (HTTPS) and sent to the Front End VIP on TCP/4443. In the case of Standard Edition servers the request would be direct rather than to the Hardware Load Balancer. See diagram below: ...