System information

BSR 64000 Configuration and Management Guide
6-10
• Query the DHCP server to verify that one IP address to MAC address
binding appears for a CM. If there is more than one IP address to MAC
address combination, one IP was assigned by DHCP and the other IP address
is statically (manually) set by a hacker. In this instance, only packets sent
from the legal source learned through DHCP are forwarded.
The DHCP lease query feature can also determine:
• If the BSR is replaced or inadvertently rebooted.
• When a CM re-registers and acquires a new lease.
• When a CM or CPE maintains its lease because it has not expired.
• When the cable interface learns about the DHCP lease through a
DHCPLEASEQUERY exchange.
• When the CM or CPE can continue passing data.
Follow these steps to enable the DHCP lease query feature:
1. Use the interface cable command in Global Configuration mode to enter the
desired cable interface, as shown below:
MOT(config-if)#interface cable {<x>/<y>}
where:
x is the slot number of the cable module.
y is the cable interface number, which is 0.
2. Use the dhcpleasequery authorization on command in Interface Configuration
mode to enable DHCP lease query messages to be exchanged between the cable
interface and DHCP server, as shown below:
MOT(config-if)#dhcpleasequery authorization on
Note: The IP helper address must be entered for the DHCP Lease Query
function to work. Refer to “Configuring the Cable Helper and IP Helper
Addresses” on page 6-4 for more information on setting the IP helper address
on the cable interface.