7-20 Riverstone Networks RS Switch Router User Guide Release 8.0
Anti-Spoofing CMTS Configuration Guide
7.8 ANTI-SPOOFING
The following examples illustrate methods for anti-spoofing using the RS.
The RS in these examples contain the following line cards:
Slot 1: 8 port 10/100 card
Slot 5: CMTS card

7.8.1 Anti-DHCP Spoofing

Anti-DHCP spoofing prevents a DHCP server that is behind a cable modem from serving as a provisioning server for
nodes on the same cable network. In this example, DHCP anti-spoofing prevents DHCP SERVER #2 from serving as
a provisioning server instead of DHCP SERVER #1.
Following, is the configuration:
! Configure the RS
cmts set headend cm.5.1 hashed-auth-str hbCgHB
cmts set uschannel cm.5.1 upstream 1 state on
! Configure the VLANs
vlan create dhcp port-based
vlan create cmts port-based
vlan add ports et.1.1 to dhcp
vlan add ports cm.5.1 to cmts
interface create ip dhcp address-netmask 50.1.1.1/16 vlan dhcp
interface create ip cmts1 address-netmask 50.2.1.1/16 vlan cmts
! Enable anti-DHCP spoofing
cmts set headend cm.5.1 anti-dhcp-spoofing enable
et.1.1
cm.5.1
50.1.1.1
DHCP SERVER 1
RS
DDEEFF: 000002 / 50.2.1.X
MODEM #2
CPE #1
DHCP SERVER 2