Reserving IP Addresses scope from DHCP without having MAC addresses

dhcpnetworking

I don't know if it belongs on serverfault or stackoverflow so you can move it if nessecary.

I am wondering if it's possible to reserve a group of IP addresses from DHCP without providing MAC Addresses to DHCP? Windows RAS does that so in DHCP Console you can see entry like Reserved for RAS for 10 or so addresses that have no MAC Address. I would like to achieve similar thing for the device that acts as DHCP Relay. I have to help to make the device send some kind of flag or empty mac address to DHCP to reserve the addresses?

For example:

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Best Answer

Windows RAS interacts with the DHCP server through management means (probably MSRPC) in order to reserve addresses - what it does will never work with a DHCP server other than a Microsoft one.

Nothing in the DHCP standard provides a means to tell a server, "I was one address for me, and a dozen for some friends" - heck, you can't even get two addresses on the same adapter. It's not a complex protocol.

Probably the best you're going to do is to have this mystery device send a bunch of fake DHCP client requests sourced from different fake MAC addresses, to stake out a bunch of addresses.

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