Reservation best practices?

[Joshua Beard]

Greetings,

This is likely a rookie question, but I thought I'd ask the list.

The scenario:
We've received many new printers on our network this week, which already had hostnames preset to conform to our standards and were setup for DHCP.  My plan was to let them get DHCP and then reserve the address for them by using the MAC.

After reading around, it looks like reservations don't work that way in ISC DHCP.  My understanding is that the reserved address cannot be in the lease pool.  Unfortunately, these printers have already received addresses in the pools of their respective subnets.

Additionally, some of the folks setting them up may have already added these printers via their IP addresses to client machines.

What's recommendations are there to handle this?  I'm thinking I'll have to set aside a block of addresses in each subnet that's not in the pool and reserve them in that and wait for them to make a new request, then adjust any client machines that are talking to them via IP.  Is this my best option?  Is there a clean way to do this with ddns in mind?

Thanks in advance,
Josh