Summary
Microsoft Skype for Business Server 2015 provides minimal support for HTTP clients that incorrectly connect to a SIP listening port because the Skype for Business Server uses port 443 for client connections in the service topologies. After you apply this update, the Skype for Business Server will include a Strict-Transport-Security header in the path where it returns any HTTP response and the underlying connection is TLS.
Note HTTP Strict Transport Security (HSTS) is an Internet Engineering Task Force (IETF) standard-compliant security feature in the header to help users connect to secure sites in a secure way, and prevent some attacks.
How to get this update
To get this update, install the December 2017 cumulative update 6.0.9319.510 for Skype for Business Server 2015, Front End server and Edge server.
