Skype for Business DHCP options for Windows and Cisco Routers

I wrote this tool a few years ago to satisfy a need to generate Skype for Business DHCP options and output them in a hex format that is easy to use on a Cisco router’s DHCP service. I had been manually generating this and after too many human errors on a large global deployment, I decided to write the tool. The tool will also replace DHCPUtil.exe and provide what is needed for a Microsoft DHCP server.

I tried to find the current Microsoft documentation on PIN Authentication requirements for 3PIP phones, but it doesn’t seem that any of it is available anymore, such as a description of the DHCPUtil.exe tool. I did find some current Poly references which I linked at the bottom of the page.

The tool can be downloaded from the Technet Gallery:

Page Link: Skype for Business and Lync DHCP Generator
EXE Link: SfB Lync DHCP Generator 1.01.exe


Providing DHCP option 120 and especially 43 offline can be a daunting task. So I took Chris Lehr’s spreadsheet calculator and improved it a little (adding some FQDN validation thanks to Kai Meyer’s excellent regex). I also added the Cisco DHCP calculations based on Elan Shudnow’s blog entry on how to do this. This was developed in Visual Basic using VS Express 2015, so I’m sure there are some .NET dependencies. Enjoy!

UPDATE 02-07-2017 – Version 1.01
– fixed bug in MS UC Vendor Class ID

Known Issues:

  • FQDN addresses starting with a digit cannot be generated as it will not pass the FQDN validation regex I am using. ie.
  • The incorrect version number is displayed in the beginning of the text output, but the correct version 1.01 is displayed at the end.



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