Chapter 29: Security
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
873
Table 110.
CLI Commands for Dual Shared Secret
Purpose
CLI Command
To configure the primary shared secret:
configure cable shared-secret <authentication-key> [hidden]
To configure the secondary (dual) shared
secret:
configure cable shared-secondary-secret <authentication-key>
[hidden]
Note: If the hidden parameter is used, then the authentication-key parameter is copied directly into the MIB variable.
If not, it must first be encrypted and then copied into the MIB variable.
To see which modems have failed
authentication:
show cable modem
Cable Modem MAC Deny List
This feature enables MSOs to prevent specific cable modems from obtaining IP addresses from the C4/c CMTS. The
purpose of this feature is to prevent malicious subscribers from cloning MAC addresses, sending virus attacks, or initiating
ping storms. The CM MAC Deny list supports a total of 1000 CM MAC addresses.
When MSOs detect the same MACs on multiple systems, they can add them to the deny list on the C4/c CMTSs where
those MACs do not belong. If a malicious user is detected by the C4/c CMTS, their modem can be added to the MAC Deny
list. Whenever a CM MAC address is added to this list, that modem is prevented from acquiring an IP address. When a
modem on the MAC Deny list attempts to range and register, the C4/c CMTS generates a debug logging message showing
the time of the attempt, the interface, and number of attempts so far.
MAC-Deny Modems are not included on the modem flap list. Their attempts to register are not included in the flap count.
The list of MAC-Deny modems is not provided by the show cable modem command. Place a modem on the MAC deny list
using the following command:
configure cable modem deny <mac>
Note: The command to assign a modem to the MAC deny list does not take effect immediately. The modem must be reset
using either one of the following commands:
clear cable modem <addr> delete
configure reset cable-modem <addr> delete