DHCPD classes - How to put unknown devices in a separate class?

[Jessica Meyer]

Hi list

Thanks for your answers - Nial, Glenn and Randall.

> class "Devices_C" {
>   match if ( substring ( option vendor-class-identifier, 0, 6 ) != "vendor1"
>   and substring (option vendor-class-identifier, 0, 6 ) != "vendor2" );
>     log ( info, "Got a packet not from a vendor1 or vendor2 device" );
>     option domain-name "devicec.example.com";
> }

This does only work if the vendor-class-identifier is set, correct?
Because I cannot trust the client that it has this option set. I tried
this statement as well, then tried to add something like "or not
(option vendor-class-identifier)" but that didn't work - I'm
unfamiliar with the syntax I think.

Actually, my overall problem is: My DHCPD receives unicast DHCP
packets from one relay (say, 172.20.0.1), but I need to give out IP
addresses according to the vendor-class-identifier option. I always
failed at that. Does anyone have an example configuration or idea how
to do this? Problem is, 172.20.0.0/24 is also a subnet, and if the
gateway is 172.20.0.1, DHCPD only gives out ip addresses from that
particular subnet.

Jess