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Cisco uBR10012 Universal Broadband Router Software Configuration Guide
OL-1520-05
Chapter4 Managing Cable Modems on the Hybrid Fiber-Coaxial Network Activating CM Upstream Address Verification
Activating CM Upstream Address Verification
CM upstream address verification ensures that only CMs that have received Dynamic Host
Configuration Protocol (DHCP) leases through the CiscouBR10012router can access the HFC network.
The CiscouBR10012router discards all packets received from or for hosts that have not received
Dynamic Host Configuration Protocol (DHCP)-assigned addresses. The default setting is "off" (CM
upstream address verification is deactivated).
To activate or deactivate CM upstream verification, use the following command in the cable interface
configuration mode:

Verifying CM Upstream Address Verification

To verify that CM upstream verification has been activated or deactivated, enter the command more
system:running-config and look for the no cable source-verify notation in the cable interface
configuration information. If CM upstream verification has been deactivated, it does not appear in this
output. If CM upstream verification has been activated, it appears in this output as
cablesource-verify, as shown in this command output excerpt:
Router# more system:running-config
Building configuration...
Current configuration:
!
interface Cable5/0/0
ip address 1.1.1.1 255.255.255.0
no keepalive
cable source-verify
cable insertion-interval 2000
cable downstream annex B
cable downstream modulation 64qam
cable downstream interleave-depth 32
cable downstream symbol-rate 5056941
cable upstream 0 frequency 15008000
cable upstream 0 fec
cable upstream 0 scrambler
no cable upstream 0 shutdown
!
Tip Be sure that you enter the correct slot and port number when you enter the cable interface
configuration mode.
Note If the CiscouBR10012router is reloaded or the Address Resolution Protocol (ARP) table is cleared,
all hosts on the network are forced to release and renew their IP addresses. Some systems might
require restarting if the IPprotocol stack is unable to renew using a broadcast IP address.
Clearing CM Counters
To clear the counters for the CMs in the station maintenance list, use one of the following commands in
cable interface configuration mode.
Command Purpose
cable source-verify [dhcp]Activates CM upstream verification. The dhcp option specifies that
queries be sent to verify unknown IP addresses in upstream data packets.
no cable source-verify Returns to the default upstream verification state.