Configuring DHCP Lease Periods on Cisco router.
You want to change the default lease period on your router.
To change the default DHCP lease time for a pool of IP addresses, use the lease configuration command:
R1(config)#ip dhcp pool 192.168.5.0 255.255.255.0
R1(dhcp-config)#lease 5 12 30
With The lease command, you are left three options: lease days, hours, minutes with hours and minutes being optional. You can specify a maximum period of 365 days, 23 hours and 59 minutes, and a minimum of 1 second. The default is 1 day.
How To Configure Cisco router to assign addresses with infinite lease period.
Use the following command:
R1(config)#ip dhcp pool HQ