Options on a client class (and possibly a list of classes per subnet) would be a new feature. I can open a separate task for that if you want it.

The default server in the yealink phone is normal and this is the default URL after a factory reset (https://updateyealink.lydis.com ....

Hi all

Great @Viacheslav ! I'll wait for the next rolling release to test this new feature. Thank you both (you and @rherold) and VyOS Team

Thanks rherold 😊

Or maybe it hasn't been implemented in the code yet

Hello all
Thanks for response but i have a bug

set service dhcp-server client-class Yealink_T42S hostname substring value 'T42S'

Sorry, I forgot to say hello