5. Renewing lease
This is similar to the first DHCP REQUEST but with a crucial difference: the client knows its IP address and that of the server. As the DHCP server is on a different subnet, requests bear the MAC address of the router.
UDP 18.104.22.168:68 (00:00:39:1C:0C:32) > 22.214.171.124:67 (00:D0:BC:00:11:22) DHCP REQUEST UDP 126.96.36.199:67 (00:D0:BC:00:11:22) > 188.8.131.52:68 (00:00:39:1C:0C:32) DHCP ACKA DHCP NAK may be returned by the DHCP server if the lease cannot be renewed, at which point the client should abandon its IP address (and may send a DHCPDISCOVER).