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Cisco CMTS Feature Guide, Release 12.3BC
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Title Pages
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Preface
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Admission Control for the Cisco Cable Modem Termination System
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Cable Duplicate MAC Address Reject for the Cisco CMTS
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Cable Interface Bundling and Virtual Interface Bundling for the Cisco CMTS
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Cable Monitor and Intercept Features on the Cisco CMTS
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COPS Engine Operation on the Cisco CMTS
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DHCP, ToD, and TFTP Services for the Cisco Cable Modem Termination System
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DOCSIS 1.1 for the Cisco CMTS
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DOCSIS 2.0 A-TDMA Services on the Cisco CMTS
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EtherChannel on the Cisco Cable Modem Termination System
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Flap List Troubleshooting for the Cisco CMTS
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Maximum CPE or Host Parameters for the Cisco Cable Modem Termination System
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N+1 Redundancy for the Cisco Cable Modem Termination System
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PacketCable and PacketCable Multimedia for the Cisco CMTS
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Point-to-Point Protocol over Ethernet Support on the Cisco CMTS
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Service Flow Admission Control for the Cisco CMTS
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Service Flow Mapping to MPLS-VPN on the Cisco CMTS
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Spectrum Management and Advanced Spectrum Management for the Cisco CMTS
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Telco Return for the Cisco CMTS
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Time-of-Day Server for the Cisco CMTS
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Unique Device Identifier Retrieval for the Cisco CMTS
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Upstream Scheduler Mode for the Cisco CMTS
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Glossary
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Feedback
Table Of Contents
DHCP, ToD, and TFTP Services for the Cisco Cable Modem Termination System
Prerequisites for DHCP, ToD, and TFTP Services
Restrictions for DHCP, ToD, and TFTP Services
Information About DHCP, ToD, and TFTP Services
How to Configure DHCP, ToD, and TFTP Services
Creating and Configuring a DHCP Address Pool for Cable Modems
Creating and Configuring a DHCP Address Pool for CPE Devices (optional)
Configuring Time-of-Day Service
Configuring A Basic All-in-One Configuration (optional)
Configuring an Advanced All-in-One Configuration (optional)
Optimizing the Use of an External DHCP Server
Configuring Cable Source Verify Option (optional)
Configuring Optional DHCP Parameters (optional)
Configuring the DHCP MAC Address Exclusion List for the cable-source verify dhcp Command
DHCP Pools for Disabling Cable Modems
Basic All-in-One Configuration Example
Advanced All-in-One Configuration Example
DHCP, ToD, and TFTP Services for the Cisco Cable Modem Termination System
Revised: June 8, 2009, 0L-1467-08
This chapter describes how to configure Cisco Cable Modem Termination System (CMTS) platforms so that they support onboard servers that provide Dynamic Host Configuration Protocol (DHCP), Time-of-Day (ToD), and Trivial File Transfer Protocol (TFTP) services for use in Data-over-Cable Service Interface Specifications (DOCSIS) networks. In addition, this chapter provides information about optional configurations that can be used with external DHCP servers.
Feature Specifications for DHCP, ToD, and TFTP Services
Finding Support Information for Platforms and Cisco IOS Software Images
Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.
Contents
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Prerequisites for DHCP, ToD, and TFTP Services
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Prerequisites for DHCP, ToD, and TFTP Services
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Restrictions for DHCP, ToD, and TFTP Services
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Information About DHCP, ToD, and TFTP Services
This section provides the following information about the DHCP, ToD, and TFTP Services feature, and its individual components:
Feature Overview
All Cisco CMTS platforms support onboard servers that provide DHCP, ToD, and TFTP services for use in DOCSIS cable networks. These servers provide the registration services needed by DOCSIS 1.0- and 1.1-compliant cable modems:
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Although cable modems do not need to successfully complete the ToD request before coming online, this allows them to add accurate timestamps to their event logs so that these logs are coordinated to the clock used on the CMTS. In addition, having the accurate date and time is essential if the cable modem is trying to register with Baseline Privacy Interface Plus (BPI+) encryption and authentication.
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You can configure and use each server separately, or you can configure an "all-in-one" configuration so that the CMTS acts as a DHCP, ToD, and TFTP server. With this configuration, you do not need any additional servers, although additional servers provide redundancy, load-balancing, and scalability.
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Internal DHCP Server
At power-up, DOCSIS cable modems send a broadcast message through the cable interface to find a DHCP server that can provide the information needed for IP connectivity across the network. After the cable modem comes online, the CPE devices connected to the cable modem can also make their own DHCP requests. You can configure all Cisco CMTS platforms to act as DHCP servers that provide the IP addressing and other networking information that is needed by DOCSIS cable modems and their CPE devices.
DHCP Field Options
In its DHCP request message, the cable modem identifies itself by its MAC hardware address. In reply, a DOCSIS-compatible DHCP server should provide, at minimum, the following fields when replying to cable modems that are authorized to access the cable network:
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If you decide to also provide IP addresses to the CPE devices connected to the cable modems, the DHCP server must also provide the following information for CPE devices:
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The DHCP server on the Cisco CMTS can also provide a number of options beyond the minimum that are required for network operation. A basic configuration is suitable for small installations as well as lab and experimental networks.
You can also configure the CMTS in a more complex configuration that uses the functionality of DHCP pools. DHCP pools are configured in a hierarchical fashion, according to their network numbers. A DHCP pool with a network number that is a subset of another pool's network number inherits all of the characteristics of the larger pool.
DHCP Security Options
Because the DOCSIS specification requires cable modems to obtain their IP addresses from a DHCP server, cable networks are susceptible to certain types of configuration errors and theft-of-service attacks, including:
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To help combat these attacks, the Cisco CMTS dynamically maintains a database that links the MAC and IP addresses of known CPE devices with the cable modems that are providing network access for those CPE devices. The CMTS builds this database using information from both internal and external DHCP servers:
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The CMTS can also use the DHCP Relay Agent Information option (DHCP option 82) to send particular information about a cable modem, such as its MAC address and the cable interface to which it is connected. If the DHCP server cannot match the information with that belonging to a cable modem in its database, the CMTS knows that the device is a CPE device. This allows the CMTS and DHCP server to retain accurate information about which CPE devices are using which cable modems and whether the devices should be allowed network access.
The DHCP Relay Agent can also be used to identify cloned modems or gather geographical information for E911 and other applications. Using the cable dhcp-insert command, users configure the CMTS to insert downstream, upstream, or hostname descriptors into DHCP packets. A DHCP server can then utilize such information to detect cloned modems or extract geographical information. Multiple types of strings can be configured as long as the maximum relay information option size is not exceeded.
Multiple DHCP Pools
You can also configure any number of DHCP pools for the DHCP server to use in assigning IP addresses. A single pool can be used for a basic configuration, or you can optionally create separate pools for cable modems and CPE devices. You can also use DHCP address pools to provide special services, such as static IP addresses, to customers who are paying for those service.
When creating multiple DHCP pools, you can configure them independently, or you can optionally create a hierarchical structure of pools that are organized according to their network numbers. A DHCP pool that has a network number that is a subset of another pool's network number inherits all of the characteristics of the larger pool. In addition to the inherited characteristics, you can further customize each pool with any number of options.
The advantage of DHCP pools is that you can create a number of different DHCP configurations for particular customers or applications, without having to repeat CLI commands for the parameters that the pools have in common. You can also change the configuration of one pool without affecting customers in other pools.
External DHCP Servers
The Cisco CMTS router provides the following optional configurations that can enhance the operation and security of external DHCP servers that you are using on the DOCSIS cable network:
Cable Source Verify Feature
To combat theft-of-service attacks, you can enable the cable source-verify command on the cable interfaces on the Cisco CMTS router. This feature uses the router's internal database to verify the validity of the IP packets that the CMTS receives on the cable interfaces, and provides three levels of protection:
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Smart Relay Feature
The Cisco CMTS supports a Smart Relay feature (the ip dhcp smart-relay command), which automatically switches a cable modem or CPE device to secondary DHCP servers or address pools if the primary server runs out of IP addresses or otherwise fails to respond with an IP address. The relay agent attempts to forward DHCP requests to the primary server three times. After three attempts with no successful response from the primary, the relay agent automatically switches to the secondary server.
When you are using the cable dhcp-giaddr policy command to specify that CPE devices should use secondary DHCP pools corresponding to the secondary addresses on a cable interface, the smart relay agent automatically rotates through the available secondary in a round robin fashion until an available pool of addresses is found. This ensures that clients are not locked out of the network because a particular pool has been exhausted.
Giaddr Field
When using separate IP address pools for cable modems and CPE devices, you can use the cable dhcp-giaddr policy command to specify that cable modems should use address from the primary pool and that CPE devices should use addresses from the secondary pool. The default is for the CMTS to send all DHCP requests to the primary DHCP server, and the secondary servers are used only if the primary server does not respond.
Time-of-Day Server
The Cisco CMTS can function as a ToD server that provides the current date and time to the cable modems and other customer premises equipment (CPE) devices connected to its cable interfaces. This allows the cable modems and CPE devices to accurately timestamp their Simple Network Management Protocol (SNMP) messages and error log entries, as well as ensure that all of the system clocks on the cable network are synchronized to the same system time.
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The current DOCSIS 1.0 and 1.1 specifications require that all DOCSIS cable modems request the following time-related fields in the DHCP request they send during their initial power-on provisioning:
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After a cable modem successfully acquires a DHCP lease time, it then attempts to contact one of the ToD servers provided in the list provided by the DHCP server. If successful, the cable modem updates its system clock with the time offset and timestamp received from the ToD server.
If a ToD server cannot be reached or if it does not respond, the cable modem eventually times out, logs the failure with the CMTS, and continues on with the initialization process. The cable modem can come online without receiving a reply from a ToD server, but it must periodically continue to reach the ToD server at least once in every five-minute period until it successfully receives a ToD reply. Until it reaches a ToD server, the cable modem must initialize its system clock to midnight on January 1, 1970 GMT.
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Because cable modems will repeatedly retry connecting with a ToD server until they receive a successful reply, you should consider activating the ToD server on the Cisco CMTS, even if you have one or more other ToD servers at the headend. This ensures that an online cable modem will always be able to connect with the ToD server on the Cisco CMTS, even if the other servers go down or are unreachable because of network congestion, and therefore will not send repeated ToD requests.
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In addition, although the DOCSIS specifications do not require that a cable modem successfully obtain a response from a ToD server before coming online, not obtaining a timestamp could prevent the cable modem from coming online in the following situations:
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TFTP Server
All Cisco CMTS platforms can be configured to provide a TFTP server that can provide the following types of files to DOCSIS cable modems:
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All Cisco CMTS platforms can be configured as TFTP servers that can upload these files to the cable modem. The files can reside on any valid device but typically should be copied to the Flash memory device inserted into the Flash disk slot on the Cisco CMTS.
In addition, the Cisco CMTS platform supports an internal DOCSIS configuration file editor in Cisco IOS Release 12.1(2)EC, Cisco IOS Release 12.2(4)BC1, and later releases. When you create a DOCSIS configuration file using the internal configuration file editor, the CMTS stores the configuration file in the form of CLI commands. When a cable modem requests the DOCSIS configuration file, the CMTS then dynamically creates the binary version of the file and uploads it to the cable modem.
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http://www.cisco.com/cisco/pub/software/portal/select.html?config=cpe-conf
For enhanced security, current versions of Cisco IOS software for Cisco CMTS platforms include a "TFTP Enforce" feature (cable tftp-enforce command) that allows you to require that all cable modems must attempt a TFTP download through the cable interface before being allowed to come online. This prevents a common theft-of-service attack in which hackers reconfigure their local network so that a local TFTP server downloads an unauthorized DOCSIS configuration file to the cable modem. This ensures that cable modems download only a DOCSIS configuration file that provides the services they are authorized to use.
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How to Configure DHCP, ToD, and TFTP Services
See the following configuration tasks required to configure DHCP service, time-of-day service, and TFTP service on a Cisco CMTS:
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All procedures are required unless marked as optional (depending on the desired network configuration and applications).
Configuring DHCP Service
To configure the DHCP server on the Cisco CMTS, use the following procedures to create the required address pools for the server to use. You can create one pool for all DHCP requests (cable modems and CPE devices), or separate pools for cable modems and for CPE devices, as desired.
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Creating and Configuring a DHCP Address Pool for Cable Modems
To use the DHCP server on the Cisco CMTS, you must create at least one address pool that defines the IP addresses and other network parameters that are given to cable modems that make DHCP requests. To create an address pool, use the following procedure, beginning in EXEC mode. Repeat this procedure as needed to create additional address pools.
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Creating and Configuring a DHCP Address Pool for CPE Devices (optional)
In addition to providing IP addresses for cable modems, the DHCP server on the Cisco CMTS server can optionally provide IP addresses and other network parameters to the customer premises equipment (CPE) devices that are connected to the cable modems on the network. To do so, create a DHCP address pool for those CPE devices, using the following procedure, beginning in EXEC mode. Repeat this procedure as needed to create additional address pools.
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DETAILED STEPS
Configuring Time-of-Day Service
This section provides procedures for enabling and disabling the time-of-day (ToD) server on the Cisco CMTS routers.
Prerequisites
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Enabling Time-of-Day Service
To enable the ToD server on a Cisco CMTS, use the following procedure, beginning in EXEC mode.
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DETAILED STEPS
Disabling Time-of-Day Service
To disable the ToD server, use the following procedure, beginning in EXEC mode.
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DETAILED STEPS
Configuring TFTP Service
To configure TFTP service on a Cisco CMTS where the CMTS can act as a TFTP server and download a DOCSIS configuration file to cable modems, perform the following steps:
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Each configuration task is required unless otherwise listed as optional.
Step 1
Most configurations of the Cisco CMTS platforms support both linear Flash and Flash disk memory cards. Linear Flash memory is accessed using the slot0 (or flash) and slot1 device names. Flash disk memory is accessed using the disk0 and disk1 device names.
For example, the following command shows a Cisco uBR7200 series router that has two linear Flash memory cards installed. The cards can be accessed by the slot0 (or flash) and slot1 device names.
Router# show file systemsFile Systems:Size(b) Free(b) Type Flags Prefixes48755200 48747008 flash rw slot0: flash:16384000 14284000 flash rw slot1:32768000 31232884 flash rw bootflash:* - - disk rw disk0:- - disk rw disk1:- - opaque rw system:- - opaque rw null:- - network rw tftp:522232 507263 nvram rw nvram:- - network rw rcp:- - network rw ftp:- - network rw scp:Router#The following example shows a Cisco uBR10012 router that has two Flash disk cards installed. These cards can be accessed by the disk0 and sec-disk0 device names.
Router# show file systemsFile Systems:Size(b) Free(b) Type Flags Prefixes- - flash rw slot0: flash:- - flash rw slot1:32768000 29630876 flash rw bootflash:* 128094208 95346688 disk rw disk0:- - disk rw disk1:- - opaque rw system:- - flash rw sec-slot0:- - flash rw sec-slot1:* 128094208 95346688 disk rw sec-disk0:- - disk rw sec-disk1:32768000 29630876 flash rw sec-bootflash:- - nvram rw sec-nvram:- - opaque rw null:- - network rw tftp:522232 505523 nvram rw nvram:- - network rw rcp:- - network rw ftp:- - network rw scp:Router#
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Router# ping 10.10.10.1Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 10.10.10.1, timeout is 2 seconds:!!!!!Success rate is 100 percent (5/5), round-trip min/avg/max = 5/6/6 msStep 4
The following example shows the file docsis.cm being transferred from the external TFTP server at IP address 10.10.10.1 to the first Flash memory disk (disk0):
Router# copy tftp disk0Address or name of remote host []? 10.10.10.1Source filename []? config-files/docsis.cmDestination filename [docsis.cm]?Accessing tftp://10.10.10.1/config-file/docsis.cm......Loading docsis.cm from 10.10.10.1 (via Ethernet2/0): !!![OK - 276/4096 bytes]276 bytes copied in 0.152 secsRouter#Step 5
Step 6
Router# dir disk0:Directory of disk0:/1 -rw- 10705784 May 30 2002 19:12:46 ubr10k-p6-mz.122-2.8.BC2 -rw- 4772 Jun 20 2002 18:12:56 running.cfg.save3 -rw- 241 Jul 31 2002 18:25:46 gold.cm4 -rw- 225 Jul 31 2002 18:25:46 silver.cm5 -rw- 231 Jul 31 2002 18:25:46 bronze.cm6 -rw- 74 Oct 11 2002 21:41:14 disable.cm7 -rw- 2934028 May 30 2002 11:22:12 ubr924-k8y5-mz.bin8 -rw- 3255196 Jun 28 2002 13:53:14 ubr925-k9v9y5-mz.bin128094208 bytes total (114346688 bytes free)Router#Step 7
Router# configure terminalRouter(config)#Step 8
Router(config)# tftp-server disk0:gold.cm alias gold.cmRouter(config)# tftp-server disk0:silver.cm alias silver.cmRouter(config)# tftp-server disk0:bronze.cm alias bronze.cmRouter(config)# tftp-server disk0:ubr924-k8y5-mz.bin alias ubr924-codefileRouter(config)# tftp-server disk0:ubr925-k9v9y5-mz.bin alias ubr925-codefileRouter(config)#
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Router(config)# service udp-small-servers max-servers no-limitRouter(config)#Step 10
Router(config)# interface cable x/yRouter(config-if)# cable tftp-enforceRouter(config-if)#You can also specify the mark-only option so that cable modems can come online without attempting a TFTP download, but the cable modems are marked in the show cable modems command so that network administrators can investigate the situation further before taking any action.
Router(config)# interface cable x/yRouter(config-if)# cable tftp-enforce mark-onlyRouter(config-if)#
Configuring A Basic All-in-One Configuration (optional)
The basic all-in-one configuration requires configuring the DHCP, ToD, and TFTP servers, as described in the following sections in this document:
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You must also have the necessary DOCSIS configuration files available for the TFTP server. You can do this in two ways:
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For an example of a basic all-in-one configuration, see the "Basic All-in-One Configuration Example" section.
Configuring an Advanced All-in-One Configuration (optional)
The advanced all-in-one configuration sample is identical to the basic configuration except that it uses a hierarchy of DHCP pools. Any DHCP pool with a network number that is a subset of another pool's network number inherits all the characteristics of that other pool. This saves having to repeat identical commands in the multiple DHCP pool configurations.
For information on the required tasks, see the following sections in this guide:
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You must also have the necessary DOCSIS configuration files available for the TFTP server. You can do this in two ways:
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For an example of an advanced all-in-one configuration, see the "Advanced All-in-One Configuration Example" section.
Optimizing the Use of an External DHCP Server
The Cisco CMTS offers a number of options that can optimize the operation of external DHCP servers on a DOCSIS cable network. See the following sections for details. All procedures are optional, depending on the needs of your network and application servers.
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Configuring Cable Source Verify Option (optional)
To enhance security when using external DHCP servers, you can optionally configure the Cable Source Verify feature with the following procedure, beginning in EXEC mode.
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SUMMARY STEPS
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enable
Example:Router> enable
Router#
Enables privileged EXEC mode. Enter your password if prompted.
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configure terminal
Example:Router# configure terminal
Router(config)#
Enters global configuration mode.
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interface cable x/y
Example:Router(config)# interface cable 4/0
Router(config-if)#
Enters cable interface configuration mode for the specified cable interface.
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cable source-verify [dhcp | leasetimer value]
Example:Router(config-if)# cable source-verify dhcpRouter(config-if)# cable source-verify leasetimer 30
Router(config-if)#
(Optional) Ensures that the CMTS allows network access only to those IP addresses that DCHP servers issued to devices on this cable interface. The CMTS examines DHCP packets that pass through the cable interfaces to build a database of which IP addresses are valid on which interface.
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no cable arp
Example:Router(config-if)# no cable arpRouter(config-if)#
(Optional) Blocks Address Resolution Protocol (ARP) requests originating from devices on the cable network. Use this command, together with the cable source-verify dhcp command, to block certain types of theft-of-service attacks that attempt to hijack or spoof IP addresses.
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exit
Example:Router(config-if)# exit
Router(config)#
Exits interface configuration mode.
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ip dhcp relay information option
Example:Router(config)# ip dhcp relay information option
Router(config)#
(Optional) Enables the CMTS to insert DHCP relay information (DHCP option 82) in relayed DHCP packets. This allows the DHCP server to store accurate information about which CPE devices are using which cable modems. You should use this command if you are also using the cable source-verify dhcp command.
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exit
Example:Router(config)# exit
Router#
Exits global configuration mode.
Configuring Optional DHCP Parameters (optional)
When using an external DHCP server, the Cisco CMTS supports a number of options that can enhance operation of the cable network in certain applications. To configure these options, use the following procedure, beginning in EXEC mode.
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enable
Example:Router> enable
Router#
Enables privileged EXEC mode. Enter your password if prompted.
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configure terminal
Example:Router# configure terminal
Router(config)#
Enters global configuration mode.
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ip dhcp smart-relay
Example:Router(config)# ip dhcp smart-relay
Router(config)#
(Optional) Enables the DHCP relay agent on the CMTS to automatically switch a cable modem or CPE device to a secondary DHCP server or address pool if the primary DHCP server does not respond to three successive requests. If multiple secondary servers have been defined, the relay agent forwards DHCP requests to the secondary servers in a round robin fashion.
Step 4
ip dhcp ping packet 0
Example:Router(config)# ip dhcp ping packet 0
Router(config)#
(Optional) Instructs the DHCP server to assign an IP address from its pool without first sending an ICMP ping to test whether a client is already currently using that IP address. Disabling the ping option can speed up address assignment when a large number of modems are trying to connect at the same time. However, disabling the ping option can also result in duplicate IP addresses being assigned if users assign unauthorized static IP addresses to their CPE devices.
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ip dhcp relay information check
Example:Router(config)# ip dhcp relay information check
Router(config)#
(Optional) Configures the DHCP server to validate the relay agent information option in forwarded BOOTREPLY messages. Invalid messages are dropped.
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interface cable x/y
Example:Router(config)# interface cable 4/0
Router(config-if)#
Enters cable interface configuration mode for the specified cable interface.
Step 7
cable dhcp-giaddr policy
Example:Router(config-if)# cable dhcp-giaddr policy
Router(config-if)#
Sets the DHCP giaddr field of DHCP request packets to the primary address for cable modems and the secondary address for CPE devices, allowing the use of separate address pools for the different clients.
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Step 8
cable helper-address address [cable-modem | host | mta | stb ]
Example:Router(config-if)# cable helper-address 10.10.10.13
Router(config-if)#
(Optional) Enables load-balancing of DHCP requests from cable modems and CPE devices by specifying different DHCP servers according to the cable interface or subinterface. You can also specify separate servers for cable modems and CPE devices.
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Step 9
cable dhcp-parse option-optnum
Example:Router(config-if)# cable dhcp-parse option-43
Router(config-if)#
(Optional) Enables the parsing of certain DHCP options.
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Step 10
exit
Example:Router(config-if)# exit
Router(config)#
Exits interface configuration mode.
Step 11
exit
Example:Router(config)# exit
Router#
Exits global configuration mode.
Configuring the DHCP MAC Address Exclusion List for the cable-source verify dhcp Command
Cisco IOS Release 12.3(13)BC introduces the ability to exclude trusted MAC addresses from standard DHCP source verification checks, as supported in previous Cisco IOS releases for the Cisco CMTS. This feature enables packets from trusted MAC addresses to pass when otherwise packets would be rejected with standard DHCP source verification. This feature overrides the cable source-verify command on the Cisco CMTS for the specified MAC address, yet maintains overall support for standard and enabled DHCP source verification processes. This feature is supported on Performance Routing Engine 1 (PRE1) and PRE2 modules on the Cisco uBR10012 router chassis.
To enable packets from trusted source MAC addresses in DHCP, use the cable trust command in global configuration mode. To remove a trusted MAC address from the MAC exclusion list, use the no form of this command. Removing a MAC address from the exclusion list subjects all packets from that source to standard DHCP source verification.
cable trust mac-address
no cable trust mac-address
Syntax Description
mac-address
The MAC address of a trusted DHCP source, and from which packets will not be subject to standard DHCP source verification.
Usage Guidelines
This command and capability are only supported in circumstances in which the Cable Source Verify feature is first enabled on the Cisco CMTS.
When this feature is enabled in addition to cable source verify, a packet's source must belong to the MAC Exclude list on the Cisco CMTS. If the packet succeeds this exclusionary check, then the source IP address is verified against Address Resolution Protocol (ARP) tables as per normal and previously supported source verification checks. The service ID (SID) and the source IP address of the packet must match those in the ARP host database on the Cisco CMTS. If the packet check succeeds, the packet is allowed to pass. Rejected packets are discarded in either of these two checks.
Any trusted source MAC address in the optional exclusion list may be removed at any time. Removal of a MAC address returns previously trusted packets to non-trusted status, and subjects all packets to standard source verification checks on the Cisco CMTS.
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For additional information about the enhanced Cable Source Verify DHCP feature, and general guidelines for its use, refer to the following documents on Cisco.com:
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http://www.cisco.com/en/US/docs/cable/cmts/feature/cblsrcvy.pdf
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http://www.cisco.com/en/US/docs/ios/cable/command/reference/cbl_book.html
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http://www.cisco.com/en/US/tech/tk86/tk803/technologies_tech_note09186a00800a7828.shtml
Configuration Examples
This section provides examples for the following configurations:
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DHCP Server Examples
The following sections gave sample configurations for configuring DHCP pools for cable modems and CPE devices:
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DHCP Pools for Cable Modems
The following examples show three typical DHCP pools for cable modems. Each pool includes the following fields:
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!ip dhcp pool cm-platinumnetwork 10.128.4.0 255.255.255.0bootfile platinum.cmnext-server 10.128.4.1default-router 10.128.4.1option 2 hex ffff.8f80option 4 ip 10.1.4.1option 7 ip 10.1.4.1lease 7 0 10!ip dhcp pool cm-goldnetwork 10.129.4.0 255.255.255.0bootfile gold.cmnext-server 10.129.4.1default-router 10.129.4.1option 2 hex ffff.8f80option 4 ip 10.1.4.1option 7 ip 10.1.4.1lease 7 0 10!ip dhcp pool cm-silvernetwork 10.130.4.0 255.255.255.0bootfile silver.cmnext-server 10.130.4.1default-router 10.130.4.1option 2 hex ffff.8f80option 4 ip 10.1.4.1option 7 ip 10.1.4.1lease 7 0 10DHCP Pools for Disabling Cable Modems
The following examples shows typical DHCP pool configurations for cable modems that disable network access for their attached CPE devices. With this configuration, the cable modem can come online and is able to communicate with the CMTS, but the CPE devices cannot access the cable network. Each pool includes the following fields:
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!ip dhcp pool DisabledModem(0010.aaaa.0001)host 10.128.1.9 255.255.255.0client-identifier 0100.10aa.aa00.01bootfile disable.cm!ip dhcp pool DisabledModem(0020.bbbb.0002)host 10.128.1.10 255.255.255.0client-identifier 0100.20bb.bb00.02bootfile disable.cmip dhcp pool DisabledModem(1010.9581.7f66)host 10.128.1.11 255.255.255.0client-identifier 0100.1095.817f.66bootfile disable.cmDHCP Pools for CPE Devices
The following examples show a typical DHCP pool for CPE devices. Each pool includes the following fields:
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!ip dhcp pool hostsnetwork 10.254.1.0 255.255.255.0default-router 10.254.1.1dns-server 10.254.1.1 10.128.1.1domain-name ExamplesDomainName.comlease 7 0 10!The following example shows a DHCP pool that assigns a permanent, static IP address to a particular CPE device. This example is identical to the previous pool except for the following commands:
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!ip dhcp pool staticPC(0001.dddd.0001)host 10.254.1.12 255.255.255.0client-identifier 0100.01dd.dd00.01default-router 10.254.1.1dns-server 10.254.1.1 10.128.1.1domain-name ExamplesDomainName.comlease 7 0 10ToD Server Example
The following example shows a typical ToD server configuration:
service udp-small-servers max-servers no-limitcable time-serverThese are the only commands required to enable the ToD server.
TFTP Server Example
The following lines are an excerpt from a configuration that includes a TFTP server. The cable tftp-enforce command is optional but recommended for each cable interface. Change the files listed with the tftp-server command to match the specific files that are on your system.
! Enable the user of unlimited small serversservice udp-small-servers max-servers no-limit!...! Enable the TFTP Enforce feature on all cable interfacesinterface Cable3/0cable tftp-enforceinterface Cable4/0cable tftp-enforceinterface Cable5/0cable tftp-enforce!!...! Enable the TFTP server and specify the files that can be! downloaded along with their aliasestftp-server disk0:gold.cm alias gold.cmtftp-server disk0:silver.cm alias silver.cmtftp-server disk0:bronze.cm alias bronze.cmtftp-server disk0:ubr924-k8y5-mz.bin alias ubr924-codefiletftp-server disk0:ubr925-k9v9y5-mz.bin alias ubr925-codefileBasic All-in-One Configuration Example
The basic "all-in-one configuration" sample below summarizes all the components described in examples in the "Configuration Examples" section. Five DOCSIS configuration files are available. The internal DOCSIS configuration file editor has been used to create four (platinum.cm, gold.cm, silver.cm, and disable.cm), and the fifth file, bronze.cm, has been loaded on to the slot0 Flash memory device. The disable.cm file disables network access for all CPE devices attached to a cable modem, and the other four files provide different levels of Quality-of-Service (QoS).
The configuration has two DHCP pools with two different address spaces. One pool provides IP addresses and platinum-level service for cable modems, and the other pool provides IP addresses for CPE devices.
!version 12.1no service pad! provides nice timestamps on all log messagesservice timestamps debug datetime msec localtimeservice timestamps log uptime! turn service password-encryption on to encrypt passwordsno service password-encryption! provides additional space for longer configuration fileservice compress-config! supports a large number of modems / hosts attaching quicklyservice udp-small-servers max-servers no-limit!hostname Router!boot system disk0:!no cable qos permission createno cable qos permission updatecable qos permission modems! permits cable modems to obtain Time of Day (TOD) from uBR7100cable time-server!! High performance DOCSIS config file, additional options may be added! 10 Mbit/sec download, 128 Kbit/sec upload speed, 10 Kbit/sec guaranteed upstream! NOTE: cable upstream 0 admission-control 150 will prevent modems from! connecting after 150% of guaranteed-bandwidth has been allocated to! registered modems. This can be used for peek load balancing.! max-burst 1600 prevents a modem with concatenation turned on from consuming! too much wire time, and interfering with VoIP traffic.! cpe max 8 limits the modem to 8 hosts connected before the CMTS refuses! additional host MAC addresses.! Timestamp option makes the config file only valid for a short period of time.!cable config-file platinum.cmservice-class 1 max-upstream 128service-class 1 guaranteed-upstream 10service-class 1 max-downstream 10000service-class 1 max-burst 1600cpe max 8timestamp!! Medium performance DOCSIS config file, additional options may be added! 5 Mbit/sec download, 128 Kbit/sec upload speed!cable config-file gold.cmservice-class 1 max-upstream 64service-class 1 max-downstream 5000service-class 1 max-burst 1600cpe max 3timestamp!! Low performance DOCSIS config file, additional options may be added! 1 Mbit/sec download, 64 Kbit/sec upload speed!cable config-file silver.cmservice-class 1 max-upstream 64service-class 1 max-downstream 1000service-class 1 max-burst 1600cpe max 1timestamp!! No Access DOCSIS config file, used to correctly shut down an unused cable modem! 1 kbit/sec download, 1 Kbit/sec upload speed, with USB/ethernet port shut down.!cable config-file disable.cmaccess-deniedservice-class 1 max-upstream 1service-class 1 max-downstream 1service-class 1 max-burst 1600cpe max 1timestamp!ip subnet-zero! Turn on cef switching / routing, anything but process switching (no ip route-cache)ip cefip cef accounting per-prefix! Disables the finger serverno ip finger! Prevents CMTS from looking up domain names / attempting to connect to! machines when mistyping commandsno ip domain-lookup! Prevents issuance of IP address that is already in use.ip dhcp ping packets 1!! DHCP reply settings for DOCSIS cable modems.! All settings here are "default response settings" for this DHCP pool.! DOCSIS bootfile (cable modem config-file) as defined above! next-server = IP address of server which sends bootfile! default-router = default gateway for cable modems, necessary to get DOCSIS files! option 4 = TOD server IP address! option 2 = Time offset for TOD, in seconds, HEX, from GMT, -28,000 = PST = ffff.8f80! option 7 = Optional SYSLOG server! Lease length, in days, hours, minutes!ip dhcp pool CableModems-Platinumnetwork 10.128.1.0 255.255.255.0bootfile platinum.cmnext-server 10.128.1.1default-router 10.128.1.1option 2 hex ffff.8f80option 4 ip 10.128.1.1option 7 ip 10.128.1.1lease 7 0 10!! DHCP reply settings for IP hosts behind DOCSIS cable modems.! All settings here are "default response settings" for this DHCP pool.! default-router = default gateway for cable modems, necessary to get DOCSIS files! dns-server = IP address for DNS server, place up to 8 addresses on the same! line as a list! NOTE: changing the DNS-server on a Windows PC, Mac, or Unix box require! reloading the OS, but changing it in the DHCP response is quick and easy.! domain-name = default domain name for the host! Lease length, in days, hours, minutes!ip dhcp pool hostsnetwork 10.254.1.0 255.255.255.0default-router 10.254.1.1dns-server 10.254.1.1 10.128.1.1domain-name ExamplesDomainName.comlease 1 0 10!!!interface FastEthernet0/0ip address 10.17.123.1 255.255.255.0no ip mroute-cacheno shutdownduplex autospeed auto!interface FastEthernet0/1no ip addressno ip mroute-cacheshutdownduplex autospeed auto!! Primary address is for cable modems, use only one, so make it large enough!! Secondary addresses are for hosts, use as many as necessary! These addresses must match the remainder of the configuration file,! or modems won't work.! cable downstream frequency sets the upconverter frequency! cable down rf-power 55, sets the upconverter output power in dBmV! each upstream interface can have a description, use it!! All four upstreams have been set to the same default frequency, don't! connect wire them together while on the same frequency!! cable upstream 0 admission-control 150: limits the number of modems! which can connect with guaranteed-bandwidth.! NOTE: will prevent some modems from connecting once this limit is hit.!! High security option:! no cable arp: prevents the uBR7100 from ever arping towards the cable modems! for any IP-mac address pairing. Forces EVERY host to use DHCP at least! once every time the uBR7100 is reloaded, or the arp table is cleared out.! Forces users to use DHCP release/renew cycle on their computers if! ARP entry is ever lost.! Makes it impossible for an end user to type in a static IP address,! or steal somebody else's IP address.!! cable-source verify dhcp: -- Forces the CMTS to populate the arp table from! the DHCP server! If the DHCP server does not have a valid DHCP lease for that IP / MAC combination,! the host is unreachable.! cable dhcp-giaddr policy: use primary IP address for modems, secondary for! hosts behind modems!!interface Cable1/0description Cable Downstream Interfaceip address 10.254.1.1 255.255.255.0 secondaryip address 10.128.1.1 255.255.255.0no keepalivecable downstream rate-limit token-bucket shapingcable downstream annex Bcable downstream modulation 64qamcable downstream interleave-depth 32cable downstream frequency 851000000cable down rf-power 55cable upstream 0 description Cable upstream interface, Northcable upstream 0 frequency 37008000cable upstream 0 power-level 0cable upstream 0 admission-control 150no cable upstream 0 shutdowncable upstream 1 description Cable upstream interface, Southcable upstream 1 frequency 37008000cable upstream 1 power-level 0cable upstream 1 admission-control 150no cable upstream 1 shutdowncable upstream 2 description Cable upstream interface, Eastcable upstream 2 frequency 37008000cable upstream 2 power-level 0cable upstream 2 admission-control 150no cable upstream 2 shutdowncable upstream 3 description Cable upstream interface, Westcable upstream 3 frequency 37008000cable upstream 3 power-level 0cable upstream 3 admission-control 150no cable upstream 3 shutdownno cable arpcable source-verify dhcpcable dhcp-giaddr policy!!! default route to Fast ethernet 0/0, probably best to set! this as an IP address so interface flaps don't create route flaps.! IP http server: enables internal http server!ip classlessno ip forward-protocol udp netbios-nsip route 0.0.0.0 0.0.0.0 FastEthernet0/0ip http server!!! Enable TFTP downloads of the silver.cm file on the Flash device! this DOCSIS config file is built using DOCSIS CPE Configurator.tftp-server slot0:bronze.cm alias bronze.cm!! Aliases for frequently used commands!alias exec scm show cable modemalias exec scf show cable flapalias exec scp show cable qos profile!line con 0exec-timeout 0 0transport input noneline aux 0speed 19200line vty 0 4session-timeout 60login!ntp clock-period 17179977ntp server 192.168.35.51endAdvanced All-in-One Configuration Example
The advanced all-in-one configuration is identical to the basic configuration, except that it uses a hierarchical structure of DHCP pools to provide unique DHCP options, such as static IP addresses, to individual cable modems and CPE devices. The DHCP pools are given unique and relevant names to simplify administration, and the cable modems and CPE devices that use these pools are specified by the client-identifier commands.
The DHCP pools for the individual cable modems and CPE devices inherit the options from the parent pools, so you do not need to specify all of the required options for those particular pools. Instead, the new pools need to specify only those commands, such as client-identifier, that should be different from the parent pools.
Because the static IP addresses that are given to the cable modems and CPE devices are in the range of 10.1.4.60 and 10.1.4.70, the ip dhcp exclude command is used to instruct the DHCP server that it should not hand out addresses in this range to other cable modems or CPE devices.
!version 12.1no service pad! provides nice timestamps on all log messagesservice timestamps debug datetime msec localtimeservice timestamps log uptime! turn service password-encryption on to encrypt passwordsno service password-encryption! provides additional space for longer configuration fileservice compress-config! supports a large number of modems / hosts attaching quicklyservice udp-small-servers max-servers no-limit!hostname Router!boot system disk0:!no cable qos permission createno cable qos permission updatecable qos permission modems! permits cable modems to obtain Time of Day (TOD) from uBR7100cable time-server!! High performance DOCSIS config file, additional options may be added! 10 Mbit/sec download, 128 Kbit/sec upload speed, 10 Kbit/sec guaranteed upstream! NOTE: cable upstream 0 admission-control 150 will prevent modems from! connecting after 150% of guaranteed-bandwidth has been allocated to! registered modems. This can be used for peek load balancing.! max-burst 1600 prevents a modem with concatenation turned on from consuming! too much wire time, and interfering with VoIP traffic.! cpe max 8 limits the modem to 8 hosts connected before the CMTS refuses! additional host MAC addresses.! Timestamp option makes the config file only valid for a short period of time.!cable config-file platinum.cmservice-class 1 max-upstream 128service-class 1 guaranteed-upstream 10service-class 1 max-downstream 10000service-class 1 max-burst 1600cpe max 8timestamp!! Medium performance DOCSIS config file, additional options may be added! 5 Mbit/sec download, 128 Kbit/sec upload speed!cable config-file gold.cmservice-class 1 max-upstream 64service-class 1 max-downstream 5000service-class 1 max-burst 1600cpe max 3timestamp!! Low performance DOCSIS config file, additional options may be added! 1 Mbit/sec download, 64 Kbit/sec upload speed!cable config-file silver.cmservice-class 1 max-upstream 64service-class 1 max-downstream 1000service-class 1 max-burst 1600cpe max 1timestamp!! No Access DOCSIS config file, used to correctly shut down an unused cable modem! 1 kbit/sec download, 1 Kbit/sec upload speed, with USB/ethernet port shut down.!cable config-file disable.cmaccess-deniedservice-class 1 max-upstream 1service-class 1 max-downstream 1service-class 1 max-burst 1600cpe max 1timestamp!ip subnet-zero! Turn on cef switching / routing, anything but process switching (no ip route-cache)ip cefip cef accounting per-prefix! Disables the finger serverno ip finger! Prevents CMTS from looking up domain names / attempting to connect to! machines when mistyping commandsno ip domain-lookup! Prevents the issuance of IP addresses in this range, allows for use in! static configurations.ip dhcp excluded-address 10.128.1.60 10.128.1.70! Prevents issuance of IP address that is already in use.ip dhcp ping packets 1!! DHCP reply settings for DOCSIS cable modems.! All settings here are "default response settings" for this DHCP pool.! DOCSIS bootfile (cable modem config-file) as defined above! next-server = IP address of server which sends bootfile! default-router = default gateway for cable modems, necessary to get DOCSIS files! option 4 = TOD server IP address! option 2 = Time offset for TOD, in seconds, HEX, from GMT, -28,000 = PST = ffff.8f80! option 7 = Optional SYSLOG server! Lease length, in days, hours, minutes!ip dhcp pool CableModems-Platinumnetwork 10.128.1.0 255.255.255.0bootfile platinum.cmnext-server 10.128.1.1default-router 10.128.1.1option 2 hex ffff.8f80option 4 ip 10.128.1.1option 7 ip 10.128.1.1lease 7 0 10!! DHCP reply settings for IP hosts behind DOCSIS cable modems.! All settings here are "default response settings" for this DHCP pool.! default-router = default gateway for cable modems, necessary to get DOCSIS files! dns-server = IP address for DNS server, place up to 8 addresses on the same! line as a list! NOTE: changing the DNS-server on a Windows PC, Mac, or Unix box require! reloading the OS, but changing it in the DHCP response is quick and easy.! domain-name = default domain name for the host! Lease length, in days, hours, minutes!ip dhcp pool hostsnetwork 10.254.1.0 255.255.255.0default-router 10.254.1.1dns-server 10.254.1.1 10.128.1.1domain-name ExamplesDomainName.comlease 1 0 10!! DHCP reply settings for a static IP address for a PC and cable modems! All settings here will override "default response settings" for this DHCP pool.! client-identifier is the ethernet MAC address of the device, preceded by 01! Thus, the Host with an mac address of 08.00.09.af.34.e2 will ALWAYS get the! same IP address! Lease length, in days, hours, minutes, set to infinite.! Use a relevant name here, as there will be lots of these entries.!ip dhcp pool staticPC(0800.09af.34e2)host 10.254.1.12 255.255.255.0client-identifier 0108.0009.af34.e2client-name staticPC(0800.09af.34e2)lease infiniteip dhcp pool cm-0050.04f9.efa0cm-host 10.128.1.65 255.255.255.0client-identifier 0100.107b.ed9b.45bootfile disable.cm!ip dhcp pool cm-0030.d002.41f5host 10.128.1.66 255.255.255.0client-identifier 0100.107b.ed9b.23bootfile silver.cm!! DHCP reply settings for a cable modem, to change from default provisioning! All settings here will override "default response settings" for this DHCP pool.! client-identifier is the ethernet MAC address of the device, preceded by 01! Thus, the modem with a mac address of 00.10.95.81.7f.66 will ALWAYS get the! same IP address! This cable modem will get the gold.cm config file, and a consistent IP address! some IP address within the DHCP pool for the cable downstream interface is! required, or the reference correct config file will NOT be issued.! Use a relevant name here, as there will be lots of these entries.!! WARNING: When changing config files for a modem, it is necessary to clear the! address with "clear ip dhcp binding <ip-address>" and then reset the modem using! "clear cable modem <mac-address> | <ip-address> reset"!ip dhcp pool goldmodemhost 10.128.1.67 255.255.255.0client-identifier 0100.1095.817f.66bootfile gold.cm!! DHCP reply settings for a disabled cable modem.! This will prevent this cable modem user from accessing the network.! client-identifier is the ethernet MAC address of the device, preceded by 01! This cable modem will get the disable.cm config file, and a consistent IP address! some IP address within the DHCP pool for the cable downstream interface is! required, or the reference correct config file will NOT be issued.! Use a relevant name here, as there will be lots of these entries.!! WARNING: When changing config files for a modem, it is necessary to clear the! address with "clear ip dhcp binding <ip-address>" and then reset the modem using! "clear cable modem <mac-address> | <ip-address> reset"!ip dhcp pool DisabledModem(0010.aaaa.0001)host 10.128.1.68 255.255.255.0client-identifier 0100.1095.817f.66bootfile disable.cm!ip dhcp pool DisabledModem(0000.bbbb.0000)client-identifier 0100.00bb.bb00.00host 10.128.1.69 255.255.255.0bootfile disable.cm!!!interface FastEthernet0/0ip address 10.17.123.1 255.255.255.0no ip mroute-cacheno shutdownduplex autospeed auto!interface FastEthernet0/1no ip addressno ip mroute-cacheshutdownduplex autospeed auto!! Primary address is for cable modems, use only one, so make it large enough!! Secondary addresses are for hosts, use as many as necessary! These addresses must match the remainder of the configuration file,! or modems won't work.! cable downstream frequency sets the upconverter frequency! cable down rf-power 55, sets the upconverter output power in dBmV! each upstream interface can have a description, use it!! All four upstreams have been set to the same default frequency, don't! connect wire them together while on the same frequency!! cable upstream 0 admission-control 150: limits the number of modems! which can connect with guaranteed-bandwidth.! NOTE: will prevent some modems from connecting once this limit is hit.!! High security option:! no cable arp: prevents the uBR7100 from ever arping towards the cable modems! for any IP-mac address pairing. Forces EVERY host to use DHCP at least! once every time the uBR7100 is reloaded, or the arp table is cleared out.! Forces users to use DHCP release/renew cycle on their computers if! ARP entry is ever lost.! Makes it impossible for an end user to type in a static IP address,! or steal somebody else's IP address.!! cable-source verify dhcp: -- Forces the CMTS to populate the arp table from! the DHCP server! If the DHCP server does not have a valid DHCP lease for that IP / MAC combination,! the host is unreachable.! cable dhcp-giaddr policy: use primary IP address for modems, secondary for! hosts behind modems!!interface Cable1/0description Cable Downstream Interfaceip address 10.254.1.1 255.255.255.0 secondaryip address 10.128.1.1 255.255.255.0no keepalivecable downstream rate-limit token-bucket shapingcable downstream annex Bcable downstream modulation 64qamcable downstream interleave-depth 32cable downstream frequency 851000000cable down rf-power 55cable upstream 0 description Cable upstream interface, Northcable upstream 0 frequency 37008000cable upstream 0 power-level 0cable upstream 0 admission-control 150no cable upstream 0 shutdowncable upstream 1 description Cable upstream interface, Southcable upstream 1 frequency 37008000cable upstream 1 power-level 0cable upstream 1 admission-control 150no cable upstream 1 shutdowncable upstream 2 description Cable upstream interface, Eastcable upstream 2 frequency 37008000cable upstream 2 power-level 0cable upstream 2 admission-control 150no cable upstream 2 shutdowncable upstream 3 description Cable upstream interface, Westcable upstream 3 frequency 37008000cable upstream 3 power-level 0cable upstream 3 admission-control 150no cable upstream 3 shutdownno cable arpcable source-verify dhcpcable dhcp-giaddr policy!!! default route to Fast ethernet 0/0, probably best to set! this as an IP address so interface flaps don't create route flaps.! IP http server: enables internal http server on uBR7100!ip classlessno ip forward-protocol udp netbios-nsip route 0.0.0.0 0.0.0.0 FastEthernet0/0ip http server!!! Enable TFTP downloads of the silver.cm file on the Flash device! this DOCSIS config file is built using DOCSIS CPE Configurator.tftp-server slot0:bronze.cm alias bronze.cm!! Aliases for frequently used commands!alias exec scm show cable modemalias exec scf show cable flapalias exec scp show cable qos profile!line con 0exec-timeout 0 0transport input noneline aux 0speed 19200line vty 0 4session-timeout 60login!ntp clock-period 17179977ntp server 192.168.35.51Additional References
For additional information related to <module feature>, refer to the following references:
Related Documents
All-In-One Configuration
For information on how to configure a Cisco CMTS that acts as a Dynamic Host Configuration Protocol (DHCP), Time-of-Day (ToD), and TFTP server in an "all-in-one configuration," see the following URL:
http://www.cisco.com/en/US/tech/tk86/tk804/technologies_configuration_example09186a0080134b34.shtmlDHCP Configuration
To configure the DHCP server beyond the minimum options given in this chapter, see the "Configuring DHCP" chapter in the "IP Addressing and Services" section of the Cisco IOS IP and IP Routing Configuration Guide, Release 12.2 at the following URL:
http://www.cisco.com/en/US/docs/ios/12_2/ip/configuration/guide/fipr_c.htmlFor information on all DHCP commands, see the "DHCP Commands" chapter in the Cisco IOS IP Command Reference, Volume 1 of 3: Addressing and Services, Release 12.2 at the following URL:
http://www.cisco.com/en/US/docs/ios/12_2/ipaddr/command/reference/fipras_r.htmlTFTP Server Command
For more information about the tftp-server command, see the "Configuring Basic File-Transfer Services" section of the Cisco IOS Configuration Fundamentals Configuration Guide, Release 12.2 at the following URL:
http://www.cisco.com/en/US/docs/ios/12_2/configfun/configuration/guide/fcf011.htmlNTP or SNTP Configuration
For information on configuring the Cisco CMTS to use NTP or SNTP to set its system clock, see the "Performing Basic System Management" chapter in the "System Management" section of the Cisco IOS Configuration Fundamentals Configuration Guide, Release 12.2, at the following URL:
http://www.cisco.com/en/US/docs/ios/12_2/configfun/configuration/guide/fcf012.htmlCable Source Verify Feature
For a more detailed description of the cable source-verify command and how it can be used to prevent certain types of denial of service attacks, see the following Tech Note on Cisco.com:
http://www.cisco.com/en/US/tech/tk86/tk803/technologies_tech_note09186a00800a7828.shtmlCalculating the Hexadecimal Value for DHCP Option 2
For information on how to calculate the hexadecimal time value that is used to set the DHCP Time Offset option (DHCP option 2), see the following URL:
http://www.cisco.com/en/US/tech/tk86/tk804/technologies_tech_note09186a0080093d76.shtmlCisco DOCSIS Configurator Tool
For information on creating DOCSIS 1.1 configuration files, you can use the Cisco DOCSIS Configurator tool, which at the time of this document's publication is available at the following URL:
http://www.cisco.com/cisco/pub/software/portal/select.html?config=cpe-confCMTS Command Reference
Cisco Broadband Cable Command Reference Guide, at the following URL:
http://www.cisco.com/en/US/docs/ios/cable/command/reference/cbl_book.htmlCisco IOS Release 12.2 Command Reference
Cisco IOS Release 12.2 Configuration Guides and Command References, at the following URL:
http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_installation_and_configuration_guides_list.htmlhttp://www.cisco.com/en/US/products/sw/iosswrel/ps1835/prod_command_reference_list.html
Cisco uBR7100 Series Universal Broadband Router Documentation
Cisco uBR7100 Series Universal Broadband Router Hardware Installation Guide, at the following URL:
http://www.cisco.com/en/US/docs/cable/cmts/ubr7100/installation/guide/hig7100.htmlCisco uBR7100 Series Universal Broadband Router Software Configuration Guide, at the following URL:
http://www.cisco.com/en/US/docs/cable/cmts/ubr7100/configuration/guide/scg7100.htmlCisco uBR7200 Series Universal Broadband Router Documentation
Cisco uBR7200 Series Universal Broadband Router Hardware Installation Guide, at the following URL:
http://www.cisco.com/en/US/docs/cable/cmts/ubr7200/installation/guide/ub72khig.htmlCisco uBR7200 Series Universal Broadband Router Software Configuration Guide, at the following URL:
http://www.cisco.com/en/US/docs/cable/cmts/ubr7200/configuration/guide/cr72scg.htmlCisco uBR10012 Universal Broadband Router Documentation
Cisco uBR10012 Universal Broadband Router Hardware Installation Guide, at the following URL:
http://www.cisco.com/en/US/docs/cable/cmts/ubr10012/installation/guide/hig.htmlCisco uBR10012 Universal Broadband Router Software Configuration Guide, at the following URL:
http://www.cisco.com/en/US/docs/cable/cmts/ubr10012/configuration/guide/scg.html
Standards
ANSI/SCTE 22-1 2002 (formerly SP-RFI-C01-011119)
Data-Over-Cable Service Interface Specification DOCSIS 1.0 Radio Frequency Interface (RFI) (http://www.cablelabs.com/cablemodem)
Data-over-Cable Service Interface Specifications Radio Frequency Interface Specification DOCSIS 1.1 (http://www.cablelabs.com/cablemodem)
DOCSIS Baseline Privacy Interface Plus Specification (http://www.cablelabs.com/cablemodem)
1 Not all supported standards are listed.
MIBs
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:
1 Not all supported MIBs are listed.
RFCs
Technical Assistance
