I've read (Microsoft Windows Server 2003 Inside Out) that dhcp clients such
as the one implemented in win xp, before going apipa, tests if the default
gateway is reachable.

If the default gateway is still reachable, a win xp (configured with dhcp)
will mantain its ip address, also if there are no more dhcp servers on the
subnet to renew the lease.

This is a very smart behaviour, but sometimes i sperimented the opposite: at
the end of the lease period a client takes an apipa address, while it's in
the same subnet and the gateway is still reachable (obviously there's no
more dhcp server, of course).

Anyone has faced this problem, doing more testing?
thanks in advance
Agostino