LYNC Device Configuration (DHCP) - Step by Step

New feature Lync 2013:
Differences between Lync 2010 and Lync 2013 is in the DHCP Option 43.
Lync 2013 support with it's devices a dedicated VLAN deployment.
Todo's before configuring DHCP:
Before we are starting the DHCP Server Option, we need to make Lync 2010/ 2013 aware of the DHCP enbaled devices.
Turn on this functionality by using this Lync Server Management Shell command as follows:
set-CsRegistrarConfiguration -EnableDHCPServer $trueIn addition, ensure that broadcast packets from the client can reach the DHCP server(s) on the Registrar. This may mean configuring DHCP relay agents to forward DHCP packets to DHCP servers on the Registrar.
DHCP Options which are requred:
  • Option 120 (SIP Servers) is defined in RFC 3361. It is used to return a list of SIP servers.
  • Option 55 is used by the device to ask the DHCP server for the values of specific options (in our case 120 and 43).
  • Option 60 is used by the client to specify the vendor for which option 43 is requested.
  • Option 43 is a complicated option: it has many sub-options and can also have many values. The effective value for option 43, IOW the value that the DHCP server will send to the client, depends on the vendor class id. So, in a sense there is a <key, value> relationship between option 60 and option 43: for the vendor specified in option 60, option 43 provides a set of sub-options that have been configured for that vendor.

First we have look into DHCP Server which is already configured.
Sure, we need this possibly for devices like a Polycom CX600.

The next screenshots let you have a look into the configured options, which the Batch will write into the DHCP Server. Surly we are Microsoft Technology interested, that's why I have only posted the MSFT DHCP Server site.

Now we coming to the configuration part:
Copy both, the DHCPUtil and the DHCPConfigScript into a shared folder or copy it onto you DHCP Server.

Next you need to prepare a table, where you are able to identify the clear text parameter which are configured in your infrastructure:

Parameter Value
SipServer The FQDN of the main Director or main Front End pool in a particular site
WebServer The FQDN of the Web Server
CertProvUrl The URL of the Lync Server Certificate Server
EmulateClient Run as a client: sending a packet to the DHCP server and receiving the response
RunConfigScript Run DHCPUtil with a script
CleanDHCPConfig Removes Lync Server options

Replace the Value text with your actual setting. E.g.:
SipServer: dirpool.lync15.dir
WebServer: poolleft.lync15.dir
CertProvUrl: https://poolleft.lync15.dir:443/CertProv/CertProvisioningService.svc

Install Virtual C++ 2008 x86 to run DHCPUtil.exe for DHCP Options, if you are not on a Lync Server    

Run the DHCPUtil.exe -SipServer: dirpool.lync15.dir -WebServer poolleft.lync15.dir -RunConfigScript

It automatically will launch the DHCPConfigScript.bat and add's all parameters, execute it and write the data into the DHCP Server.

At the end you can validate your setting with the command:
DHCPUtil.exe -EmulateClient

This is all and easy. For validation purposes, open your DHCP Server and check, like I have shown in the screenshots that all your option are written.


References Lync 2010:

References Lync 2013:


  1. Hello Thomas,

    What do we need to achieve failover for Lync devices in case when a pool is failed over to the backup pool?

    Can you please provide an overview of what is the expected behavior in that case?



  2. Option 120 goodness here. :)


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