I have a large network (100+ nodes) on which I run Win2000 Server for DHCP. I had the lease time set to 21 days and for a year there was no problem. However, lately I've been getting a significant number of addresses with "This address is already in use" added to them in the description section. I reduced the lease time to 7 days and waited for the original 21 day leases to expire and the number of these has decreased, but I still have a dozen or so at any given time.
What is causing this and how can I fix it?