ISC DHCPD options - vendor-class-identifier

Hi,

We are currently using ZTP to download software & configs to our juniper EX 4300 48T switches. We are using a rasperry pi as the DHCP server and FTP server. In the dhcpd.conf file, we tried setting the rule using this syntax:

if option vendor-class-identifier = "ex-4300 48T";

However, this does not work unless we include the serial number of the device as well in the syntax. But we would like to filter only based on models i.e: ex-4300, qfx -5200 e.t.c to be inclusive of all the individual serial numbers.

Has anyone else experienced this? would appreciate if you can share the syntax used.

Thanks.