Cisco SR2016T-NA Reference Manual page 238

cable source-verify
The following example shows how to configure the cable interface so that the CMTS can verify IP
addresses that are on a different subnet than the one that the cable interface is using:
Router# configure terminal
Router(config)# ip cef
Router#(config) interface c7/0/0
Router(config-if)# ip verify unicast source reachable-via rx
Router(config-if)# cable source-verify dhcp
Router(config-if)#
The following example shows the error message that is displayed if you try to configure the leasetimer
option on a subinterface, instead of an interface:
Router# configure terminal
Router#(config) interface c1/0.1
Router(config-subif)# cable source-verify dhcp
Router(config-subif)# cable source-verify leasetimer 120
% Invalid input detected at '^' marker.
Router(config-subif)#
Related Commands Command
cable arp
cable helper-address
cable dhcp-giaddr
cable logging badipsource
cable relay-agent-option
cable source-verify
leasequery-filter
downstream
cable source-verify
leasequery-filter upstream
clear cable logging
ip dhcp relay information
option
ip dhcp smart-relay
ip verify unicast reverse-
path
Cisco Broadband Cable Command Reference Guide
2-226
Description
Enables or disables the use of the ARP protocol for CMs and their
CPE devices.
Specifies a destination IP address for User Datagram Protocol (UDP)
broadcast (DHCP) packets.
Modifies the GIADDR field of DHCPDISCOVER and
DHCPREQUEST packets with a Relay IP address before they are
forwarded to the DHCP server.
Logs error messages about bad IP source addresses on the cable
interfaces.
Enables the system to insert the CM MAC address into a DHCP
packet received from a CM or host and forward the packet to a DHCP
server.
Controls the number of DHCP LEASEQUERY request messages that
are sent for unknown IP addresses on all cable downstream interfaces
on the Cisco CMTS router.
Controls the number of DHCP LEASEQUERY request messages that
are sent for unknown IP addresses per each service ID (SID) on an
upstream.
Removes all error messages about bad IP source addresses on the
cable interfaces from the error log buffer.
Enables the system to insert the CM MAC address into a DHCP
packet received from a CM or host and forward the packet to a DHCP
server.
Monitors client retransmissions when address pool depletion occurs.
Enables Unicast Reverse Path Forwarding (Unicast RPF), which
checks each packet received on an interface to verify that the packet's
source IP address appears in the routing tables as belonging to that
interface, so as to prevent spoofed IP source addresses.
Chapter 2 Cisco CMTS Configuration Commands
OL-1581-08