Once completed the DNS discovery phase, the discovered records are logged in the client This is started almost immediately from when the client first launches This is done by the DNS resolver manager service. However, first it must discovery the SIP domain and obtain and resolve the correct DNS records in order to send the sign in requests. Once the hardware has been discovered and initialised, the client will then attempt to sign in. Once complete the media device manager then sets the default device for both ear and microphone including their respective volume settings Then the media device service discovers available microphones in the same manner and retrieves Once discovered, the earphone is set as default and the volume settings retrieved. Next up is the media device service (I keep calling it a service – but it really is a method within the code) discovers the earphone to be used as the primary peripheral.

The client does not actually log the network adapter / interface it has chosen, but it does log the ones that it believe cannot be used The interface that has the perceived route to the network (default route or defined route).The network adapter preference order in Network Connection settings.

From experience this is decided by two variables: Once set, the client then decides which networking adapter to use for its connection.

Once discovered, the client then proceeds to set that device as the default video media device Therefore the client first interrogates the system to see if it has a webcam available using it’s media manager service Seems only logical that the client must first discover what peripherals and hardware it has to work with. (Apologies in advance for the abundance of screenshots). First, to gather the behaviour I interrogated the local application log file and followed the log from client launch to first instant message. In an attempt to explain this process I have put together a workflow chart that lists all the key decision / request points the client makes on its journey to sign in the user which we will come to later (If you don’t want to read – scroll to the bottom). What is the actual workflow and behaviour of the client when a user attempts to login from a workstation? I wanted to add to these by looking at the process from a client perspective. There are some great deep dive articles on the internet about the Lync / Skype for Business sign in process.

Skype sign in registration