DHCP renewal rebinding
A DHCP renewal occurs when a DHCP lease expires. The DHCP host will contact the original leasing DHCP server and request a new lease. A renewal simply renews the lease time. The actual IP address and the MAC address in the server entry, and any DHCP options used all remain the same.
A rebinding is when a host will remove all network information it may have previously obtained from a DHCP server and will begin from scratch. It sends out a broadcast asking for a DHCP server to respond and binds to the server that responds successfully.
When a host attempts to perform a DHCP renew and it fails for some reason, it will then attempt a rebind.