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Cisco IOS XR IP Addresses and Services Command Reference, Release 3.6
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Preface
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Access List Commands on Cisco IOS XR Software
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ARP Commands on Cisco IOS XR Software
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Cisco Express Forwarding Commands on Cisco IOS XR Software
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DHCP Commands on Cisco IOS XR Software
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Host Services and Applications Commands on Cisco IOS XR Software
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HSRP Commands on Cisco IOS XR Software
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LPTS Commands on Cisco IOS XR Software
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Network Stack IPv4 and IPv6 Commands on Cisco IOS XR Software
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Prefix List Commands on Cisco IOS XR Software
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Transport Stack Commands on Cisco IOS XR Software
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VRRP Commands on Cisco IOS XR Software
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Index
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Table Of Contents
DHCP Commands on Cisco IOS XR Software
dhcp relay information check disable
pd (prefix-delegation - DHCP IPv6 pool)
pd (prefix-delegation - DHCP IPv6 interface)
DHCP Commands on Cisco IOS XR Software
This chapter describes the Cisco IOS XR software commands used to configure and monitor the Dynamic Host Configuration Protocol (DHCP).
allow-hint
To allow the server to delegate a valid client-suggested prefix in the solicit and request messages, use the allow-hint command in DHCP IPv6 interface server configuration mode. To disable the delegation of a valid client-suggested prefix, use the no form of the command.
allow-hint
no allow-hint
Syntax Description
This command has no arguments or keywords.
Defaults
DHCPv6 service on an interface is disabled.
Command Modes
DHCP IPv6 interface server configuration
Command History
Release 3.4.0
This command was introduced on the Cisco CRS-1 and the Cisco XR 12000 Series Router.
Release 3.5.0
No modification.
Release 3.6.0
No modification.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
The allow-hint command enables the server to delegate a client-suggested prefix in the solicit and request messages if the prefix in the associated local prefix pool is a valid prefix and it is not assigned to any other solicit and request messages. Otherwise, the hint is ignored, and a prefix is delegated from the free list in the pool.
Task ID
Examples
The following is an example of the allow-hint command:
RP/0/RP0/CPU0:router# configureRP/0/RP0/CPU0:router(config)# dhcp ipv6 interface pos 0/5/0/0 serverRP/0/RP0/CPU0:router(config-dhcpv6-if)# allow-hintclear dhcp ipv6 binding
To delete automatic client bindings from the Dynamic Host Configuration Protocol (DHCP) for IPv6 binding table, use the clear ipv6 dhcp binding command in EXEC mode.
clear dhcp ipv6 binding [ipv6-address]
Syntax Description
Command Default
No default behavior or values
Command Modes
EXEC
Command History
Release 3.4.0
This command was introduced on the Cisco CRS-1 and the Cisco XR 12000 Series Router.
Release 3.5.0
No modification.
Release 3.6.0
No modification.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
The clear ipv6 dhcp binding command is used as a server function.
A binding table entry on the DHCP for IPv6 server is automatically:
•
Created whenever a prefix is delegated to a client from the configuration information pool
•
•
If the clear ipv6 dhcp binding command is used with the optional ipv6-address argument specified, only the binding for the specified client is deleted. If the clear ipv6 dhcp binding command is used without the ipv6-address argument, then all automatic client bindings are deleted from the DHCP for IPv6 binding table.
Task ID
Examples
The following example specifies DHCP for IPv6 binding database agent parameters:
RP/0/RP0/CPU0:router# clear dhcp ipv6 bindingRelated Commands
database
To configure a Dynamic Host Configuration Protocol (DHCP) for IPv6 binding database agent, use the database command in DHCP IPv6 configuration mode. To delete the database agent, use the no form of this command.
database agent-URL [write-delay seconds] [timeout seconds]
no database agent-URL
Syntax Description
Defaults
Write-delay default is 300 seconds.
Timeout default is 300 secondsCommand Modes
DHCP IPv6 configuration
Command History
Release 3.4.0
This command was introduced on the Cisco CRS-1 and Cisco XR 12000 Series Router.
Release 3.5.0
No modification.
Release 3.6.0
No modification.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
The database command specifies DHCP for IPv6 binding database agent parameters. The user may configure multiple database agents.
The write-delay keyword specifies how often, in seconds, that DHCP sends database updates. By default, DHCP for IPv6 server waits 300 seconds before sending any database changes.
The timeout keyword specifies how long, in seconds, the router waits for a database transfer. Infinity is defined as 0 seconds, and transfers that exceed the timeout period are aborted. By default, the DHCP for IPv6 server waits 300 seconds before aborting a database transfer. When the system is going to reload, there is no transfer timeout so that the binding table can be stored completely.
Task ID
Examples
The following example specifies DHCP for IPv6 binding database agent parameters:
RP/0/RP0/CPU0:router# configureRP/0/RP0/CPU0:router(config)# dhcp ipv6RP/0/RP0/CPU0:router(config-dhcpv6)# database tftp://10.0.0.1/dhcp-bindingRelated Commands
destination (DHCP IPv6)
To specify a destination address to which client messages are forwarded and to enable DHCP for IPv6 relay service on the interface, use the destination command in DHCP IPv6 interface relay configuration mode. To remove a relay destination on the interface or delete an output interface for a destination, use the no form of this command.
destination {ipv6 address} interface
no destination {ipv6 address} interface
Syntax Description
Defaults
Relay function is disabled and there is no relay destination on the interface.
Command Modes
DHCP IPv6 interface relay configuration
Command History
Release 3.4.0
This command was introduced on the Cisco CRS-1 and Cisco XR 12000 Series Router.
Release 3.5.0
No modification.
Release 3.6.0
No modification.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
The destination command specifies a destination address to which client messages are forwarded and enables DHCP for IPv6 relay service on the interface. When relay service is enabled on an interface, a DHCP for IPv6 message received on that interface is forwarded to all configured relay destinations. The incoming DHCP for IPv6 message may have come from a client on that interface, or it may have been relayed by another relay agent.
The relay destination can be a unicast address of a server or another relay agent, or it may be a multicast address. There are the following two types of relay destination addresses:
•
•
•
If no output interface is configured for a destination, the output interface is determined by routing tables. In this case, it is recommended that a unicast or multicast routing protocol be running on the router.
Multiple destinations can be configured on one interface, and multiple output interfaces can be configured for one destination. When the relay agent relays messages to a multicast address, it sets the hop limit field in the IPv6 packet header to 32.
Unspecified, loopback, and node-local multicast addresses are not acceptable as the relay destination. If any one of them is configured, the message "Invalid destination address" is displayed.
Note that it is not necessary to enable the relay function on an interface for it to accept and forward an incoming relay reply message from servers. By default, the relay function is disabled, and there is no relay destination on an interface. The no form of the command removes a relay destination on an interface or deletes an output interface for a destination. If all relay destinations are removed, the relay service is disabled on the interface.
The DHCP for IPv6 client, server, and relay functions is mutually exclusive on an interface. When one of these functions is already enabled and a user tries to configure a different function on the same interface, one of the following messages is displayed: "Interface is in DHCP client mode," "Interface is in DHCP server mode," or "Interface is in DHCP relay mode."
Task ID
Examples
The following is an example of the destination command on a Packet over Sonet/SDH (POS) interface:
RP/0/RP0/CPU0:router(config)# dhcp ipv6RP/0/RP0/CPU0:router(config-dhcpv6)# interface pos 0/5/0/0 relayRP/0/RP0/CPU0:router(config-dhcpv6-if)# destination 10:10::10Related Commands
dhcp ipv6
To enable Dynamic Host Configuration Protocol (DHCP) for IPv6 and to enter DHCP IPv6 configuration mode, use the dhcp ipv6 command in global configuration mode. To disable, use the no form of this command.
dhcp ipv6
no dhcp ipv6
Syntax Description
This command has no arguments or keywords.
Command Modes
Global configuration
Command History
Release 3.6.0
This command was introduced on the Cisco CRS-1 and Cisco XR 12000 Series Router.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Use the dhcp ipv6 command to enter DHCP IPv6 configuration mode.
Task ID
Examples
The following example shows how to enable DHCP for IPv6:
RP/0/RP0/CPU0:router(config)# dhcp ipv6RP/0/RP0/CPU0:router (config-dhcpv6)#Related Commands
dhcp relay information check disable
To configure a Dynamic Host Configuration Protocol (DHCP) server to not validate the relay agent information option in forwarded BOOTREPLY messages, use the dhcp relay information check disable command in global configuration mode. To enable the information check and return to the default behavior, use the no form of this command.
dhcp relay information check disable
no dhcp relay information check disable
Syntax Description
This command has no arguments or keywords.
Defaults
DHCP validates the relay agent information option.
Command Modes
Global configuration
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
By default, DHCP validates the relay agent information option in forwarded BOOTREPLY messages. Use the dhcp relay information check disable command to disable the information check.
Task ID
Examples
The following example shows how to configure the relay agent to not validate the relay information option (Option 82) in a BOOTREPLY:
RP/0/RP0/CPU0:router(config)# dhcp relay information check disableRelated Commands
dhcp relay information option
To configure a Dynamic Host Configuration Protocol (DHCP) server to insert the DHCP relay agent information option in forwarded BOOTREQUEST messages, use the dhcp relay information option command in global configuration mode. To disable the insertion of relay information into forwarded BOOTREQUEST messages, use the no form of this command.
dhcp relay information option
no dhcp relay information option
Syntax Description
This command has no arguments or keywords.
Defaults
No default behavior or values
Command Modes
Global configuration
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Use the dhcp relay information option command to configure a DHCP server to insert the DHCP relay agent information option in forwarded BOOTREQUEST messages. Use the no form of this command to restore the default setting.
This command is used by cable access router termination systems. This functionality enables a DHCP server to identify the user (cable access router) sending the request and initiate appropriate action based on this information. By default, DHCP does not insert relay information.
Task ID
Examples
The following example shows how to enable command functionality and configure a DHCP server to insert the DHCP relay agent information option in forwarded BOOTREQUEST messages:
RP/0/RP0/CPU0:router(config)# dhcp relay information optionRelated Commands
dhcp relay information policy
To configure the information reforwarding policy for a Dynamic Host Configuration Protocol (DHCP) relay agent (what a relay agent should do if a message already contains relay information), use the dhcp relay information policy command in global configuration mode. To restore the default relay information policy, use the no form of this command.
dhcp relay information policy {drop | keep | replace}
no dhcp relay information policy {drop | keep | replace}
Syntax Description
Defaults
The DHCP server replaces existing relay information.
Command Modes
Global configuration
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Use the dhcp relay information policy command to configure the information reforwarding policy for a DHCP relay agent. Use the no form of this command to restore the default relay information policy.
This command is used by cable access router termination systems. When a DHCP relay agent receives a message from another DHCP relay agent, relay information might already be present in the message. By default, the relay information from the previous relay agent is replaced.
Task ID
Examples
The following examples show how to configure a DHCP relay agent to drop messages with existing relay information, keep existing information, and replace existing information, respectively:
RP/0/RP0/CPU0:router(config)# dhcp relay information policy dropRP/0/RP0/CPU0:router(config)# dhcp relay information policy keepRP/0/RP0/CPU0:router(config)# dhcp relay information policy replaceRelated Commands
dhcp server
To enable Dynamic Host Configuration Protocol (DHCP) services on a networking device, use the dhcp server command in global configuration mode. To disable DHCP services, use the no form of this command.
dhcp server
no dhcp server
Syntax Description
This command has no arguments or keywords.
Defaults
DHCP services are disabled, which means the relay agent is off.
Command Modes
Global configuration
Command History
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
When this command is enabled, by default the relay agent is on.
Task ID
Examples
The following example shows how to enable DHCP services:
RP/0/RP0/CPU0:router(config)# dhcp serverRelated Commands
distance
To specify an administrative distance for Dynamic Host Configuration Protocol (DHCP) for IPv6 Prefix Delegation, use the distance command in DHCP IPv6 configuration mode. To delete an administrative distance, use the no form of this command.
distance administrative distance
no distance administrative distance
Syntax Description
Defaults
administrative distance: 1
Command Modes
DHCP IPv6 configuration
Command History
Release 3.4.0
This command was introduced on the Cisco CRS-1 and Cisco XR 12000 Series Router.
Release 3.5.0
No modification.
Release 3.6.0
No modification.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Task ID
Examples
The following is an example of setting the DHCP administrative distance to 200 using the distance command:
RP/0/RP0/CPU0:router(config)# dhcp ipv6RP/0/RP0/CPU0:router (config-dhcpv6)# distance 200Related Commands
Enables Dynamic Host Configuration Protocol (DHCP) for IPv6 and enters DHCP IPv6 configuration mode.
dns-server
To specify the Domain Name System (DNS) IPv6 servers available to a Dynamic Host Configuration Protocol (DHCP) for IPv6 client, use the dns-server command in DHCP IPv6 pool configuration mode. To remove the DNS server list, use the no form of this command.
dns-server ipv6-address
no dns-server ipv6-address
Syntax Description
ipv6-address
IPv6 address of a DNS server.
This argument must be in the form documented in RFC 2373, where the address is specified in hexadecimal using 16-bit values between colons.
Defaults
When a DHCP for IPv6 pool is first created, no DNS IPv6 servers are configured.
Command Modes
DHCP IPv6 pool configuration
Command History
Release 3.4.0
This command was introduced on the Cisco CRS-1 and Cisco XR 12000 Series Router.
Release 3.5.0
No modification.
Release 3.6.0
No modification.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Multiple Domain Name System (DNS) server addresses can be configured by issuing this command multiple times. New addresses do not overwrite old addresses.
Task ID
Examples
The following is an example of setting the DNS server name using the dns-server command:
RP/0/RP0/CPU0:router(config)# dhcp ipv6 pool pool1RP/0/RP0/CPU0:router(config-dhcpv6-pool)# dns-server 10:10::10Related Commands
Configures a Dynamic Host Configuration Protocol (DHCP) for the IPv6 server configuration information pool and enters DHCP for IPv6 pool configuration mode.
domain-name (DHCP IPv6 pool)
To configure a domain name for a Dynamic Host Configuration Protocol (DHCP) for IPv6 client, use the domain-name command in DHCP IPv6 pool configuration mode. To remove the domain name, use the no form of this command.
domain-name domain
no domain-name
Syntax Description
Defaults
When a DHCP for IPv6 pool is first created, no domain name for clients is configured.
Command Modes
DHCP IPv6 pool configuration
Command History
Release 3.4.0
This command was introduced on the Cisco CRS-1 and Cisco XR 12000 Series Router.
Release 3.5.0
No modification.
Release 3.6.0
No modification.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Multiple Domain Name System (DNS) domain names can be configured by issuing the domain-name command multiple times. The new domain name does not overwrite existing domain names.
Task ID
Examples
The following is an example of how to configure a DHCP IPv6 domain name using the domain-name command:
RP/0/RP0/CPU0:router(config)# dhcp ipv6 pool pool1RP/0/RP0/CPU0:router(config-dhcpv6-pool)# domain-name howie.comRelated Commands
Configures a Dynamic Host Configuration Protocol (DHCP) for the IPv6 server configuration information pool and enters DHCP for IPv6 pool configuration mode.
duid
To define the Dynamic Host Configuration Protocol (DHCP) the unique identification (DUID) on a specified device, use the duid command in DHCP IPv6 configuration mode. To delete an administrative distance, use the no form of this command.
duid duid name
no duid duid name
Syntax Description
Defaults
DUID-LL as defined in Section 9.4 of RFC3315
Command Modes
DHCP IPv6 configuration
Command History
Release 3.4.0
This command was introduced on the Cisco CRS-1 and Cisco XR 12000 Series Router.
Release 3.5.0
No modification.
Release 3.6.0
No modification.
Usage Guidelines
For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Use the duid command to configure the DHCP unique identifier on a specified device. Use the no form of this command to restore the default.
Task ID
Examples
The following is an example of how to create an IPv6 DHCP unique identifier (DUID) of 0002000000090CC084D303000912 using the duid command:
RP/0/RP0/CPU0:router(config)# dhcp ipv6RP/0/RP0/CPU0:router(config-dhcpv6)# duid 0002000000090CC084D303000912Related Commands
Enables Dynamic Host Configuration Protocol (DHCP) for IPv6 and enters DHCP IPv6 configuration mode.
Displays the DHCP DUID on a specified device.
interface (DHCP)
To enable Dynamic Host Configuration Protocol (DHCP) for IPv6 on an interface, use the interface command in DHCP IPv6 configuration mode. To disable DHCPv6 on an interface, use the no form of the command.
interface interface-type interface-instance {server | relay}
Syntax Description
Defaults
No default behavior or values
Command Modes
DHCP IPv6 configuration
Command History
Release 3.4.0
This command was introduced on the Cisco CRS-1 and Cisco XR 12000 Series Router.
Release 3.5.0
No modification.
Release 3.6.0
No modification.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Task ID
Examples
The following is an example of enabling the DHCP interface mode on a Packet over Sonet/SDH (POS) interface using the interface command:
RP/0/RP0/CPU0:router(config)# dhcp ipv6RP/0/RP0/CPU0:router(config-dhcpv6)# interface POS 0/5/0/0 relayRelated Commands
Enables Dynamic Host Configuration Protocol (DHCP) for IPv6 and enters DHCP IPv6 configuration mode.
Displays DHCP for IPv6 interface information.
pd (prefix-delegation - DHCP IPv6 pool)
To specify a manually configured numeric prefix to be delegated to a specified client (and optionally a specified identity association for prefix delegation [IAPD] for that client), use the pd command in DHCP IPv6 pool configuration mode. To remove the prefix, use the no form of this command.
pd ipv6-prefix/prefix-length client-DUID [iaid iaid] [lifetime]
Syntax Description
Defaults
No manually configured prefix delegations exist.
Command Modes
DHCP IPv6 pool configuration
Command History
Release 3.4.0
This command was introduced on the Cisco CRS-1 and Cisco XR 12000 Series Router.
Release 3.5.0
No modification.
Release 3.6.0
No modification.
Usage Guidelines
To use this command, you must be in a user group associated with a task group that includes the proper task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
Task ID
Examples
The following is an example of the pd command in DHCP IPv6 pool configuration mode:
RP/0/RP0/CPU0:router(config)# dhcp ipv6 pool pool1