I deleted a range of ip addresses. I needed to give up the ip addresses
to another IT team. The problem is 3 of the addresses on the deleted
range are still in use by unknown hosts. The range was configured as
dynamic bootp and dhcp.

Is it possible that these 3 ip addresses were assigned with bootp as
permanent assignment to some kind of network device. I have tried to use
nbtstat and ping to get a host name on this addresses without success.

Should I change the ranges on my dhcp server to just dynamic dhcp?

Thank you in advanced!