enforce an option in response
ISC DHCP configs use this trick (from Dan's samples):
option wpad code 252 = text; .... # Windows doesn't put WPAD on its PRL, but does consume it. option dhcp-parameter-request-list = concat(option dhcp-parameter-request-list, fc);
The dhcp-parameter-request-list (aka PRL) option in received packets is patched to add the code fc (252) so responses will include it.
This feature was ported to Kea as the always-send option-data flag.