[brk]

Are you saying that the DHCP server pings (ICMP or ARP) each address and re-leases the ones that don't get a response?

The DHCP will ping an address before leasing it, and if it gets a response then it will not lease that address.

[m_eiman]

I don't think this is true at our office (running a Cisco DHCP server). We get conflicts when putting a device with a static IP in the dhcp range, and I'm almost sure that they respond to ping.