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. 1server.contoso.com.
- The incorrect version number is displayed in the beginning of the text output, but the correct version 1.01 is displayed at the end.