DHCP Lease Management

The DHCP server keeps track of all leased IP addresses along with their corresponding MAC addresses and lease end times. DHCP server records the IP address assignment into a Lease Information Table.

DHCP Server Lease Information
MAC	IP	Lease Time
host5 MAC	host5 IP	5 hours

If host1 requests an IP address, its lease information eventually will be added to this table once an IP address assignment takes place with discovery, offering, use request, and acknowledgment steps outlined above.

DHCP Server Lease Information
MAC	IP	Lease Time
host5 MAC	host5 IP	5 hours
host1 MAC	host1 IP	5 hours

Renew Lease

Host operating systems periodically send renew lease requests based on how the OS has been configured.

When an IP address lease time is about to expire, the host may send a request to renew its IP address lease time. The DHCP server replies with an acknowledgment if the request is granted.