Up to now we had assigned static IP-addresses to our users and I am
just about to change this into permanent leases obtained from
DHCP-server, bound to the MAC-address.
Is it possible to prevent users from assigning static IP addresses
further on (e.g. for their private laptops), if these addresses are in
a pool of excluded addresses on our DHCP server? Unfortunately it
seems that you can assign any IP-address as long as it is not used on
the network.

Our users have administrative rights on their (XP-)workstations and we
do not want to forbid users do bring their private laptops, but we
want them not to setup IP addresses by their own.

Thank you,