A reality of any system is that temporary things become permanent and some of the brightest can do dumb things. Sometimes cleaning up a messy setup still leaves some hard points that just can't be changed.
Either way we sometimes end up with excluding IPs from a range, enough that just splitting pools is a very ugly work around.
Being able to exclude an IP from a DHCP Pool/IP range would go long ways to simplifying this. It is something we had way back in NetWare days where we could easily set a single IP to be reserved. I would make administrative life easier in many environments as the image of perfection is just a fantasy.
Two scenarios are :
- a static IP that the DHCP just ignores.
- a DHCP IP that is always only handed out to one fixed host, such as by selecting an existing assignment and selecting either permanent or a much longer lease than the rest of the pool/range.