Making the Cisco IOS DHCP server useful
August 8, 2010 Leave a comment
Yay for learning! Two of the features that I was under the impression were missing from an IOS based DHCP server are infact present:
1) The ability to ping clients prior to handing out an address:
Router(config)# ip dhcp ping packets 5
Specifies the number of ping packets the DHCP server sends to a pool address before assigning the address to a requesting client.
Router(config)# ip dhcp ping timeout 850
Specifies the amount of time the DHCP server waits for a ping reply from an address pool.
2) The ability to retain a DHCP leases table across reboots:
Router(config)#ip dhcp database flash:router-dhcp write-delay 60 timeout 10
Configure DHCP database location on a physical storage medium, this prevents the router from loosing all of it’s lease data after a reboot. By default, the router maintains the dhcp bindings in NVRAM.