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Setting Up DHCP Server Options Manually for Lync 2010/2013 Phones

Lync Phone Edition requires a number of DHCP options to allow the phones to “find their way home” to the pool and sign in. The setup is the same for 2010 and 2013.

The Options required are:

  • Option 42: NTP Server
  • Option 43: Certificate Service Provisioning URL
  • Option 120: SIP Server

 

These can be worked out and setup on a DHCP server via an exe and a .bat file Tom Pacyk has a good post on the automatic deployment route here and Jeff Schertz has lots of detail on the options here

The bat file route works great, but often you’ll find Admins understandably nervous when you hand then an .exe .bat to run on their DHCP server (and the exe relies on Visual C++ Redistributable) , but fear not, you can setup all the options manually.

I’m doing this for Lync 2013 with Server 2012, but the steps for Lync 2010 and 2003/2008/R2 DHCP servers are similar.

 

DHCPUtil is at C:\Program Files\Common Files\Microsoft Lync Server 2013

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The following command will generate the input values we need

DHCPUtil.exe -SipServer lonlyncpool01.lab1.com –WebServer  lonlyncpool01webint.lab1.com

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Scope before Options are set

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First We’ll point to an NTP Server

Server Options/Configure Options

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NTP Server added

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The other options require
• Option 43: Certificate Service Provisioning URL
• Option 120: SIP Server

First we define a new vendor class.

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Click Add and type the following, you need to Type the ASCII part, that will generate the Binary. Check your numbers match for typo’s.

 

dhcpvendor

 

 

 

 

 

 

 

 

 

 

 

 

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We can see all these options in place

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Back in Predefined Options, Choose DHCP Standard Options, Add…

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Next

Server Options/ Configure Options

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Tick each option and add the info generated in DHCPUtil

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Note if you make a typo you have to delete the whole field and retype it, you can’t edit “mid string”. Also watch out for the initial “.” that starts the ASCII string, you ‘ll need to delete that.

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And Under Server Options, DHCP Standard Options, choose 120 UCSipServer and

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Time Server

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DNs Search List

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Jeff also recommends adding the 004 Time Server value (and be sure to enter your time server in DNS records as per the article)

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You should have the following server options

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and scope options

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You can test if your DHCP config is correct from a machine that would hit that DHCP server and DHCPUtil.exe -emulateclient

It will send a broadcast out

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and should get a response with the options and success

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Test-CsPhoneBootStrap is also a useful test

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If you are hitting any issues double check your input for typo’s, it’s really easy to have an single character error, or even “.” that will stop the options working

About the author

Tom Arbuthnot

A Microsoft MVP and Microsoft Certified Master, Tom Arbuthnot is Principal Solutions Architect at Microsoft Collaboration specialists Modality Systems.

Tom stays up to date with industry developments and shares news and his opinions on his blog, Microsoft Teams Podcast and email list. He is a regular speaker at events around the world.

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Tom Talks Microsoft Teams and Microsoft 365 Collaboration news and opinions