Dhcp dns updating
The device will then automatically perform a DNS query for the hostname for each domain name which may have been passed via those DHCP options.
Typically the certificate issued to the Lync Front End server is from an internal private Certificate Authority, which unfortunately means the device cannot automatically download the update without intervention.
How can a device which cannot register to the server download an update from the server when it needs to first register to be provided the device update server information?
This might mean that the device would instead need to be connected to and registered to Lync 2010 server first, then updated to CU7 or higher, no? There is one alternative which would allow any previous version of Lync Phone Edition to download an update package directly from a Lync 2013 server without even the ability to first successfully register to it.
Microsoft continues to release semi-quarterly Cumulative Updates of firmware for the various LPE models.
In the round of releases in December 2012 and January 2013 (aka CU7) official support for Lync Server 2013 was added, as well dropping the ‘2010’ from the previous name of .
Lync Phone Edition will only attempt to retrieve the root certificate from the internal, Active Directory published CA during registration attempts, it was not programmed to perform this same action automatically upon bootup.
So in this case user-intervention is required by attempting to sign-in to the Lync Server.
The oldest tested version which could successfully register to a Lync 2013 server is 3.5.6907.187.
The registration does not need to actually succeed so if the phone is running a vey old version incapable of registering to the Lync server for some reason, or an invalid PIN is used simply to speed up the process it does not matter.
Simply initiating the registration process is sufficient to trigger the root certificate retrieval process via DHCP Option 43.
The Device Out of Box section shown at the bottom of this page in Tech Net lists the requirements to support this registration-less device process.
A network capture run on the Lync server will show the following traffic indicating that the phone has requested to establish a TLS session with the Lync Server, which then passes its server certificate to the phone in the following message.
This little-known behavior is hardcoded into all firmware releases.