We have a bunch of IOT gadgets which will share cabling with a customer's regular LAN. We would like them to be logically separate. Let's say the regular LAN uses 198.162.x.x, and we want to use 10.10.x.x. There will be enough of these gadgets that using static addresses for them is not practical. They will not need to communicate with any of the customer's equipment by way of the LAN but are completely independent in that regard.
The LAN itself (cabling, switches, etc) is not our hardware - we don't administer it and don't want to complicate the existing useage by the people who do. We cannot expect to use VLANS, or that the existing switches will support that, and we can't add additional hardware such as relays. We just want to piggy-back on the existing cabling infrastucture. The regular LAN will be Windows workstations, our devices will be running some flavor of GNU/Linux.
What I have read so far about multiple dhcp servers on the same LAN is either a) "Don't do it, this is an error", or b) "Yes, this is fine if they are cooperating and load sharing and and on the same logical network, and if it does not matter from which server a client gets its address".
It appears that dhcp clients may use a number of options, including user-defined ones. Is there a way to set up a dchp server (our hardware) and dhcp clients (also our hardware) so that the clients will only accept address offers from our dhcp server and reject or ignore offers from any other dhcp server?
Specifically, is there a way for a dhcp client to recognize and act on "option dhcp-server-identifier"? It seems to me that this should be possible but I have not found any examples or discussion of this.