Cisco IOS XR IP Addresses and Services Command Reference for the Cisco CRS Router, Release 4.2.x
DHCP Commands
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DHCP Commands

DHCP Commands

This chapter describes the Cisco IOS XR software commands used to configure and monitor Dynamic Host Configuration Protocol (DHCP).

For detailed information about DHCP concepts, configuration tasks, and examples, refer to the Cisco IOS XR IP Addresses and Services Configuration Guide for the Cisco CRS Router.

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 Dynamic Host Configuration Protocol (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 keywords or arguments.

Command Default

DHCPv6 service on an interface is disabled.

Command Modes

DHCP IPv6 interface server configuration

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Usage Guidelines

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

Task ID

Operations

ip-services

read, write

Examples

The following is an example of the allow-hint command:

RP/0/RP0/CPU0:router# configure
RP/0/RP0/CPU0:router(config)# dhcp ipv6 interface pos 0/5/0/0 server
RP/0/RP0/CPU0:router(config-dhcpv6-if)# allow-hint

broadcast-flag policy check

To configure Dynamic Host Configuration Protocol (DHCP) IPv4 Relay to broadcast only BOOTREPLY packets if the DHCP IPv4 broadacst flag is set in the DHCP IPv4 header, use the broadcast-flag policy check command in DHCP IPv4 relay profile configuration submode . By default, the DHCP IPv4 Relay always broadcasts BOOTREPLY packets. To restore the default, use the no form of this command.

broadcast-flag policy{ check}

no broadcast-flag policy{ check}

Syntax Description

check

Checks the broadcast flag in packets.

unicast-always

Sets the broadcast-flag policy to unicast-always.

Command Default

Relay agent always broadcasts DHCP IPv4 packets to a client.

Command Modes

DHCP IPv4 relay profile configuration

Command History

Release

Modification

Release 3.7.0

This command was introduced.

Release 4.2.0

This command was supported for BNG.

Usage Guidelines

Task ID

Task ID

Operations

ip-services

read, write

Examples

This an example of the broadcast-flag policy check command:

RP/0/RP0/CPU0:router# config
RP/0/RP0/CPU0:router(config)# dhcp ipv4
RP/0/RP0/CPU0:router(config-dhcpv4)# profile client relay
RP/0/RP0/CPU0:router(config-dhcpv4-relay-profile)# broadcast-flag policy check

Related Commands

Command

Description

dhcp ipv4

Enables DHCP for IPv4 and enters DHCP IPv4 configuration mode.

Configures how a relay agent processes BOOTREQUEST messages that already contain a nonzero giaddr attribute.

helper-address

Configures the DHCP relay agent to relay packets to a specific DHCP server.

interface (relay profile)

Specifies a relay profile on an interface.

relay information check

Configures a DHCP server to validate the relay agent information option in forwarded BOOTREPLY messages.

relay information option

Enables the system to insert a DHCP relay agent information option in forwarded BOOTREQUEST messages to a DHCP server.

relay information option allow-untrusted

Configures the DHCP component to not drop BOOTREQUEST messages that have the relay information option set and the giaddr set to zero.

relay information policy

Configures how a relay agent processes BOOTREQUEST messages that already contain a relay information option.

vrf (relay profile)

Specifies a relay profile on a VRF.

clear 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

ipv6-address

(Optional) Address of a DHCP for an IPv6 client.

This argument must be in the form documented in RFC 2373 where the address is specified in hexadecimal using 16-bit values between colons.

Command Default

No default behavior or values

Command Modes

EXEC

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Usage Guidelines

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
  • Updated when the client renews, rebinds, or confirms the prefix delegation
  • Deleted when the client releases all the prefixes in the binding voluntarily, all prefixes' valid lifetimes have expired, or an administrator runs the clear ipv6 dhcp binding command.

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

Task ID

Operations

ip-services

execute

Examples

The following example specifies DHCP for IPv6 binding database agent parameters:


RP/0/RP0/CPU0:router# clear dhcp ipv6 binding

Related Commands

Command

Description

show dhcp ipv6 database

Displays the DHCP for the IPv6 binding database information.

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

agent-URL

A Flash, NVRAM, FTP, TFTP, or Remote Copy Protocol (RCP) uniform resource locator.

write-delay seconds

(Optional) How often (in seconds) DHCP for IPv6 sends database updates. The default is 300 seconds. The minimum write delay is 60 seconds.

imeout seconds

(Optional) Length of time, in seconds, the router waits for a database transfer.

Command Default

Write-delay default is 300 seconds.

Timeout default is 300 seconds

Command Modes

DHCP IPv6 configuration

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Usage Guidelines

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

Task ID

Operations

ip-services

read, write

Examples

The following example specifies DHCP for IPv6 binding database agent parameters:


RP/0/RP0/CPU0:router# configure
RP/0/RP0/CPU0:router(config)# dhcp ipv6
RP/0/RP0/CPU0:router(config-dhcpv6)# database tftp://10.0.0.1/dhcp-binding

Related Commands

Command

Description

dhcp ipv6

Enables Dynamic Host Configuration Protocol (DHCP) for IPv6 and enters DHCP IPv6 configuration mode.

interface (DHCP)

Enables DHCP for IPv6 on an interface.

show dhcp ipv6 database

Displays the DHCP for the IPv6 binding database information.

destination (DHCP IPv6)

To specify a destination address to which client messages are forwarded and to enable Dynamic Host Configuration Protocol (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-path-id

no destination ipv6 address interface-path-id

Syntax Description

ipv6 address address

IPv6 address in the form documented in RFC 2373, where the address is specified in hexadecimal using 16-bit values between colons.

interface-path-id

Either a physical interface instance or a virtual interface instance as follows:

  • Physical interface instance. Naming notation is rack/slot/module/port and a slash between values is required as part of the notation.
    • rack: Chassis number of the rack.
    • slot: Physical slot number of the modular services card or line card.
    • module: Module number. A physical layer interface module (PLIM) is always 0.
    • port: Physical port number of the interface.
    Note   

    In references to a Management Ethernet interface located on a route processor card, the physical slot number is alphanumeric (RP0 or RP1) and the module is CPU0. Example: interface MgmtEth0/RP1/CPU0/0.

  • Virtual interface instance. Number range varies depending on interface type.

For more information about the syntax for the router, use the question mark (?) online help function.

Command Default

Relay function is disabled and there is no relay destination on the interface.

Command Modes

DHCP IPv6 interface relay configuration

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Usage Guidelines

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:

  • A link-scoped unicast or multicast IPv6 address, for which a user must specify an output interface
  • A global unicast IPv6 address, for which a user can specify an output interface for this kind of address.
  • A global or site-scope multicast IPv6 address, for which a user can specify an output interface for this kind of address if 'mhost ipv6 default-interface' is specified.

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

Task ID

Operations

ip-services

read, write

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 ipv6 
RP/0/RP0/CPU0:router(config-dhcpv6)# interface pos 0/5/0/0 relay
RP/0/RP0/CPU0:router(config-dhcpv6-if)# destination 10:10::10

Related Commands

Command

Description

interface (DHCP)

Enables DHCP for IPv6 on an interface.

dhcp ipv4

To enable Dynamic Host Configuration Protocol (DHCP) for IPv4 and to enter DHCP IPv4 configuration mode, use the dhcp ipv4 command in Global Configuration mode. To disable DHCP for IPv4 and exit the DHCP IPv4 configuration mode, use the no form of this command.

dhcp ipv4

no dhcp ipv4

Syntax Description

This command has no keywords or arguments.

Command Modes

None

Command Modes

Global Configuration
mode

Command History

Release

Modification

Release 3.7.0

This command was introduced.

Usage Guidelines

Use the dhcp ipv4 command to enter DHCP IPv4 configuration mode.

Task ID

Task ID

Operations

ip-services

read, write

Examples

This example shows how to enable DHCP for IPv4:


RP/0/RP0/CPU0:router# dhcp ipv4
RP/0/RP0/CPU0:router(config-dhcpv4)#

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 the DHCP for IPv6, use the no form of this command.

dhcp ipv6

no dhcp ipv6

Syntax Description

This command has no keywords or arguments.

Command Modes

Global Configuration
mode

Command History

Release

Modification

Release 3.6.0

This command was introduced.

Release 4.3.0

This command was supported for BNG.

Usage Guidelines

Task ID

Task ID

Operations

ip-services

read, write

Examples

This example shows how to enable DHCP for IPv6:


RP/0/RP0/CPU0:router(config)# dhcp ipv6
RP/0/RP0/CPU0:router(config-dhcpv6)#

Related Commands

Command

Description

database

Configures a Dynamic Host Configuration Protocol (DHCP) for IPv6 binding database agent.

distance

Specifies an administrative distance for Dynamic Host Configuration Protocol (DHCP) for IPv6 Prefix Delegation.

pool (DHCP IPv6)

Configures a Dynamic Host Configuration Protocol (DHCP) for the IPv6 server configuration information pool and enters DHCP for IPv6 pool configuration mode.

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

administrative distanc e

User defined distance. The range is 1 to 255.

Command Default

administrative distance : 1

Command Modes

DHCP IPv6 configuration

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Usage Guidelines

Task ID

Task ID

Operations

ip-services

read, write

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 ipv6
RP/0/RP0/CPU0:router(config-dhcpv6)# distance 200

Related Commands

Command

Description

dhcp ipv6

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 an appropriate 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.

Command Default

When a DHCP for IPv6 pool is first created, no DNS IPv6 servers are configured.

Command Modes

DHCP IPv6 pool configuration

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Usage Guidelines

Multiple Domain Name System (DNS) server addresses can be configured by issuing this command multiple times. New addresses do not overwrite old addresses.

The DNS server is defined in DHCP IPv6 server profile and DHCP IPv6 server profile class configuration. If the same parameters are defined in the class scope, then the values defined in the class scope takes precedence.

Task ID

Task ID

Operations

ip-services

read, write

Examples

This is an example of setting the DNS server name using the dns-server command:

RP/0/RP0/CPU0:router(config)# dhcp ipv6 pool pool1
RP/0/RP0/CPU0:router(config-dhcpv6-pool)# dns-server 10:10::10

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 an appropriate configuration mode. To remove the domain name, use the no form of this command.

domain-name domain

no domain-name

Syntax Description

domain

Specifies the domain name string to be used by the client.

Command Default

When a DHCP for IPv6 pool is first created, no domain name for clients is configured.

Command Modes

DHCP IPv6 pool configuration

Usage Guidelines

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.

The domain name is defined in DHCP IPv6 server profile and DHCP IPv6 server profile class configuration. If the same parameters are defined in the class scope, then the values defined in the class scope takes precedence.

Task ID

Task ID

Operations

ip-services

read, write

Examples

This 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 pool1
RP/0/RP0/CPU0:router(config-dhcpv6-pool)# domain-name howie.com

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

duid name

IPv6 DHCP unique identifier (DUID) in hex format. The length of DUID word should be even.

Command Default

DUID-LL as defined in Section 9.4 of RFC3315

Command Modes

DHCP IPv6 configuration

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Usage Guidelines

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

Task ID

Operations

ip-services

read, write

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 ipv6
RP/0/RP0/CPU0:router(config-dhcpv6)# duid 0002000000090CC084D303000912

Related Commands

Command

Description

dhcp ipv6

Enables Dynamic Host Configuration Protocol (DHCP) for IPv6 and enters DHCP IPv6 configuration mode.

giaddr policy

To configure how Dynamic Host Configuration Protocol (DHCP) IPv4 Relay processes BOOTREQUEST packets that already contain a nonzero giaddr attribute, use the giaddr policy command in DHCP IPv4 profile relay configuration submode. To restore the default giaddr policy, use the no form of this command.

giaddr policy { replace | drop }

no giaddr policy { replace | drop }

Syntax Description

replace

Replaces the existing giaddr value with a value that it generates.

drop

Drops the packet that has an existing nonzero giaddr value.

Command Default

DHCP IPv4 relay retains the existing nonzero giaddr value in the DHCP IPv4 packet received from a client value .

Command Modes

DHCP IPv4 profile relay configuration

Command History

Release

Modification

Release 3.7.0

This command was introduced.

Usage Guidelines

The giaddr policy command affects only the packets that are received from a DHCP IPv4 client that have a nonzero giaddr attribute.

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following example shows how to use the giaddr policy command:


RP/0/RP0/CPU0:router# config
RP/0/RP0/CPU0:router(config)# dhcp ipv4
RP/0/RP0/CPU0:router(config-dhcpv4)# profile client relay
RP/0/RP0/CPU0:router(config-dhcpv4-relay-profile)# giaddr policy drop

Related Commands

Command

Description

dhcp ipv4

Enables DHCP for IPv4 and enters DHCP IPv4 configuration mode.

helper-address

Configures the DHCP relay agent to relay packets to a specific DHCP Server.

interface (relay profile)

Specifies a relay profile on an interface.

relay information check

Configures a DHCP server to validate the relay agent information option in forwarded BOOTREPLY messages.

relay information option

Enables the system to insert a DHCP relay agent information option in forwarded BOOTREQUEST messages to a DHCP server.

relay information option allow-untrusted

Configures the DHCP component to not drop BOOTREQUEST messages that have the relay information option set and the giaddr set to zero.

Configures how a relay agent processes BOOTREQUEST messages that already contain a relay information option.

helper-address

To configure the Dynamic Host Configuration Protocol (DHCP) IPv4 and IPv6 relay agent to relay BOOTREQUEST packets to a specific DHCP server, use the helper-address command in an appropriate configuration mode. Use the no form of this command to clear the address.

helper-address [ vrf vrf-name ] [ address] [ giaddr gateway-address]

no helper-address [ vrf vrf-name ] [ address] [ giaddr gateway-address]

Syntax Description

vrf-name

(Optional) Specifies the name of a particular VRF.

address

IPv4 and Pv6 address in four part, dotted decimal format.

giaddr gateway-address

Specifies the gateway address to use in packets relayed to server.

Command Default

Helper address is not configured.

Command Modes

DHCP IPv4 profile relay configuration

Command History

Release

Modification

Release 3.7.0

This command was introduced.

Usage Guidelines

A maximum of upto eight helper addresses can be configured.

Task ID

Task ID

Operations

ip-services

read, write

Examples

This example shows how to set the helper-address for a VRF using the helper-address command DHCP IPv4 profile relay configuration mode:

RP/0/RP0/CPU0:router# config
RP/0/RP0/CPU0:router(config)# dhcp ipv4
RP/0/RP0/CPU0:router(config-dhcpv4)# profile client relay
RP/0/RP0/CPU0:router(config-dhcpv4-relay-profile)# helper-address vrf v1 10.10.10.1

This example shows how to set the helper-address for a VRF using the helper-address command DHCP IPv4 profile proxy configuration mode:

RP/0/RP0/CPU0:router# config
RP/0/RP0/CPU0:router(config)# dhcp ipv4
RP/0/RP0/CPU0:router(config-dhcpv4)# profile client proxy
RP/0/RP0/CPU0:router(config-dhcpv4-relay-profile)# helper-address vrf v1 10.10.10.1 giaddr 10.10.10.10

Related Commands

Command

Description

dhcp ipv4

Enables Dynamic Host Configuration Protocol (DHCP) for IPv4 and enters DHCP IPv4 configuration mode.

interface (relay profile)

Specifies a relay profile on an interface.

relay information check

Configures a DHCP server to validate the relay agent information option in forwarded BOOTREPLY messages.

relay information option

Enables the system to insert a DHCP relay agent information option in forwarded BOOTREQUEST messages to a DHCP server.

relay information option allow-untrusted

Configures the DHCP component to not drop BOOTREQUEST messages that have the relay information option set and the giaddr set to zero.

relay information policy

Configures how a relay agent processes BOOTREQUEST messages that already contain a relay information option.

interface (DHCP)

To enable Dynamic Host Configuration Protocol (DHCP) for IPv4 on an interface, use the interface command in the appropriate configuration mode. To disable DHCPv4 on an interface, use the no form of the command.

interface type interface-path-id { server | relay }

interface type interface-path-id { server | relay }

Syntax Description

type

Interface type. For more information, use the question mark (?) online help function.

interface-path-id

Physical interface or virtual interface.

Note   

Use the show interfaces command to see a list of all interfaces currently configured on the router.

For more information about the syntax for the router, use the question mark (?) online help function.

server

Enables service on the specified interface using the pool for prefix delegation.

relay

Specifies a destination address.

Command Default

None

Command Modes

DHCP IPv4 configuration

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Task ID

Task ID

Operations

ip-services

read, write

Examples

This 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 ipv4
RP/0/RP0/CPU0:router(config-dhcpv4)# interface POS 0/5/0/0 relay

Related Commands

Command

Description

dhcp ipv4

Enables Dynamic Host Configuration Protocol (DHCP) for IPv4 and enters DHCP IPv4 configuration mode.

interface (relay profile)

To configure a relay profile on an interface, use the interface (relay profile) command in Dynamic Host Configuration Protocol (DHCP) IPv4 configuration mode. To disable this feature, use the no form of the command.

interface interface-type interface-path-id { none | relay }

no interface interface-type interface-path-id { none | relay }

Syntax Description

interface-type

Interface type. For more information, use the question mark (?) online help function.

interface-path-id

Either a physical interface instance or a virtual interface instance.

none

Disables DHCP at the specified interface.

relay

Specifies a relay profile for the interface.

Command Modes

DHCP IPv4 configuration

Command History

Release

Modification

Release 3.7.0

This command was introduced.

Usage Guidelines

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following example shows how to configure a relay profile on an interface:

RP/0/RP0/CPU0:router# config
RP/0/RP0/CPU0:router(config)# dhcp ipv4
RP/0/RP0/CPU0:router(config-dhcpv4)# interface pos 0/1/4/1 
RP/0/RP0/CPU0:router(config-dhcpv4)# interface pos 0/1/4/1 relay profile client

Related Commands

Command

Description

broadcast-flag policy check

Configures a relay agent to only broadcast DHCP IPv4 BOOTREPLY messages to a client, if the DHCP IPv4 broadcast flag is set in the DHCP IPv4 header.

dhcp ipv4

Enables Dynamic Host Configuration Protocol (DHCP) for IPv4 and enters DHCP IPv4 configuration mode.

Configures how a relay agent processes BOOTREQUEST messages that already contain a nonzero giaddr attribute.

Configures the DHCP relay agent to relay packets to a specific DHCP Server.

relay information check

Configures a DHCP server to validate the relay agent information option in forwarded BOOTREPLY messages.

relay information option

Enables the system to insert a DHCP relay agent information option in forwarded BOOTREQUEST messages to a DHCP server.

relay information option allow-untrusted

Configures the DHCP component to not drop BOOTREQUEST messages that have the relay information option set and the giaddr set to zero.

Configures how a relay agent processes BOOTREQUEST messages that already containa relay information option.

vrf (relay profile)

Specifies a relay profile on a VRF.

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 Dynamic Host Configuration Protocol (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

ipv6-prefix

(Optional) Specified IPv6 prefix.

This argument must be in the form documented in RFC 2373, where the address is specified in hexadecimal using 16-bit values between colons

/prefix-length

Length of the IPv6 prefix. A decimal value that indicates how many of the high-order contiguous bits of the address comprise the prefix (the network portion of the address).

client-DUID

The DHCP unique identifier (DUID) of the client to which the prefix is delegated.

iaid iaid

(Optional) Identity association identifier (IAID), which uniquely identifies an IAPD on the client.

lifetime

(Optional) Sets a length of time during which the requesting router is allowed to use the prefix. The following values can be used:

  • valid-seconds—Length of time, in seconds, that the prefix remains valid for the requesting router to use.
  • valid-seconds preferred-seconds—Length of time, in seconds, that the prefix remains valid for the requesting router to use, plus the length of time after which client should re-check that it still has the prefix.
  • at—Absolute point in time where the prefix is no longer valid and no longer preferred.
  • preferred-seconds—Length of time, in seconds, that the prefix remains preferred for the requesting router to use.
  • infinite—Unlimited lifetime. This value can be used in place of valid-seconds or preferred-seconds value.
  • valid-month valid-date valid-year valid-time—Fixed duration of time for hosts to remember router advertisements. The format used can be oct 24 2003 11:45 or 24 oct 2003 11:45.
  • preferred-month preferred-date preferred-year preferred-time—Fixed duration of time for hosts to remember router advertisements. The format used can be oct 24 2003 11:45 or 24 oct 2003 11:45.
  • at valid-timestamp—Absolute point in time (rather than duration) for the valid-timestamp.The prefix is valid up to valid-timestamp.
  • at valid-timestamp preferred-timestamp—Absolute point in time (rather than duration) for the valid-timestamp and preferred time-stamp. The client should confirm that it has the prefix after preferred-timestamp; however, the time-stamp is still valid up to valid-timestamp.

Command Default

No manually configured prefix delegations exist.

Command Modes

DHCP IPv6 pool configuration

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Usage Guidelines

Task ID

Task ID

Operations

ip-services

read, write

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 
RP/0/RP0/CPU0:router(config-dhcpv6-pool)# pd 2001:420:10::/48 0002000000090CC084D303000912

Related Commands

Command

Description

pool (DHCP IPv6)

Configures a Dynamic Host Configuration Protocol (DHCP) for the IPv6 server configuration information pool and enters DHCP for IPv6 pool configuration mode.

pd (prefix-delegation - DHCP IPv6 interface)

To allow the identification of a client based on client connection to a specific interface, use the pd command in DHCP IPv6 interface server configuration mode. To remove the prefix, use the no form of this command.

pd ipv6 prefix prefix -length[ lifetime]

no pd ipv6 prefix prefix -length[ lifetime]

Syntax Description

ipv6-prefix

(Optional) Specified IPv6 prefix.

This argument must be in the form documented in RFC 2373, where the address is specified in hexadecimal using 16-bit values between colons

/prefix-length

Length of the IPv6 prefix. A decimal value that indicates how many of the high-order contiguous bits of the address comprise the prefix (the network portion of the address).

lifetime

(Optional) Sets a length of time over which the requesting router is allowed to use the prefix. The following values can be used:

  • valid-lifetime—The length of time, in seconds, that the prefix remains valid for the requesting router to use.
  • at—Specifies absolute points in time where the prefix is no longer valid and no longer preferred.
  • infinite—Indicates an unlimited lifetime.
  • preferred-lifetime—The length of time, in seconds, that the prefix remains preferred for the requesting router to use.
  • valid-month valid-date valid-year valid-time—A fixed duration of time for hosts to remember router advertisements. The format used can be oct 24 2003 11:45 or 24 oct 2003 11:45.
  • preferred-month preferred-date preferred-year preferred-time—A fixed duration of time for hosts to remember router advertisements. The format used can be oct 24 2003 11:45 or 24 oct 2003 11:45.

Command Default

No manually configured prefix delegations exist.

Command Modes

DHCP IPv6 interface server configuration

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Usage Guidelines

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following is an example of the pd command in DHCP IPv6 pool configuration mode:
RP/0/RP0/CPU0:router(config)# dhcp ipv6
RP/0/RP0/CPU0:router(config-dhcpv6)# pool pool1 
RP/0/RP0/CPU0:router(config-dhcpv6-pool)# exit 
RP/0/RP0/CPU0:router(config-dhcpv6)# interface POS 0/5/0/0 server
RP/0/RP0/CPU0:router(config-dhcpv6-if)# pd 2001:420:10::/48
RP/0/RP0/CPU0:router(config-dhcpv6-if)# pool pool1

Related Commands

Command

Description

interface (DHCP)

Enables DHCP for IPv6 on an interface.

pool (DHCP IPv6)

To configure a Dynamic Host Configuration Protocol (DHCP) for the IPv6 server configuration information pool and enter DHCP for IPv6 pool configuration mode, use the pool command in either DHCP IPv6 configuration mode or DHCP IPv6 interface relay configuration mode. To delete a DHCP for IPv6 pool, use the no form of this command.

pool poolname

no pool poolname

Syntax Description

poolname

User-defined name for the local prefix pool. The pool name can be a symbolic string (such as “Engineering”) or an integer (such as 0).

Command Default

No DHCP for IPv6 pools are configured.

Command Modes


            DHCP IPv4
            IPv6 configuration
        

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Usage Guidelines

Use the pool command to create a DHCP for IPv6 server configuration information pool. When the pool command is enabled, the configuration mode changes to DHCP for IPv6 pool configuration mode. In this mode, the administrator can configure pool parameters, such as prefixes to be delegated and Domain Name System (DNS) servers.

Once the DHCP for IPv6 configuration information pool has been created, use the server command to associate the pool with a server on an interface.

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following example show how to enter pool configuration mode using the pool command:

RP/0/RP0/CPU0:router(config)# dhcp ipv6
RP/0/RP0/CPU0:router(config-dhcpv6)# pool pool1
RP/0/RP0/CPU0:router(config-dhcpv6-pool)#

Related Commands

Command

Description

dhcp ipv6

Enables Dynamic Host Configuration Protocol (DHCP) for IPv6 and enters DHCP IPv6 configuration mode.

show dhcp ipv6 pool

Displays DHCP for IPv6 configuration information pool information.

preference

To configure the preference value, use the preference command in DHCP IPv6 interface server configuration mode. To disable the preference value, use the no form of the command.

preference preference value

no preference

Syntax Description

preference value

Preference value carried in the preference option in the advertise message sent by the server. The range is from 0 to 255.

Command Default

The preference value defaults to zero.

Command Modes

DHCP IPv6 interface server configuration

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Usage Guidelines

The preference command configures a preference value. If the preference value is configured and it is not 0, the server adds a preference option to carry the preference value for the advertise message to a client to affect the selection of a server by client.

Task ID

Task ID

Operations

ip-services

read, write

Related Commands

Command

Description

interface (DHCP)

Enables DHCP for IPv6 on an interface.

profile relay

To configure a relay profile for the Dynamic Host Configuration Protocol (DHCP) IPv4 component and to enter the profile relay mode, use the profile relay command in DHCP IPv4 configuration mode. To disable this feature and exit the profile relay mode, use the no form of this command.

profile profile name relay

no profile profile name relay

Syntax Description

profile name

Name that uniquely identifies the relay profile.

Command Modes

DHCP IPv4 configuration

Command History

Release

Modification

Release 3.7.0

This command was introduced .

Usage Guidelines

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following example shows how to use the profile relay command:

RP/0/RP0/CPU0:router(config)# dhcp ipv4
RP/0/RP0/CPU0:router(config-dhcpv4)# profile client relay

Related Commands

Command

Description

broadcast-flag policy check

Configures a relay agent to only broadcast DHCP IPv4 BOOTREPLY messages to a client, if the DHCP IPv4 broadcast flag is set in the DHCP IPv4 header.

dhcp ipv4

Enables DHCP for IPv4 and enters DHCP IPv4 configuration mode.

Configures how a relay agent processes BOOTREQUEST messages that already contain a nonzero giaddr attribute.

Configures the DHCP relay agent to relay packets to a specific DHCP Server.

interface (relay profile)

Specifies a relay profile on an interface.

relay information check

Configures a DHCP server to validate the relay agent information option in forwarded BOOTREPLY messages.

relay information option

Enables the system to insert a DHCP relay agent information option in forwarded BOOTREQUEST messages to a DHCP server.

relay information option allow-untrusted

Configures the DHCP component to not drop BOOTREQUEST messages that have the relay information option set and the giaddr set to zero.

Configures how a relay agent processes BOOTREQUEST messages that already contain a relay information option.

vrf (relay profile)

Specifies a relay profile on a VRF.

rapid-commit

To enable clients that specify the Rapid Commit option in their Solicit messages to receive immediate address assignment Reply messages, use the rapid-commit command in Dynamic Host Configuration Protocol (DHCP) IPv6 interface server mode. To disable DHCP for IPv6 service on an interface, use the no form of this command.

rapid-commit

no rapid-commit

Command Default

Rapid commit is disabled.

Command Modes

DHCP IPv6 interface server configuration

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Usage Guidelines

The rapid-commit command enables or disables rapid commit. If enabled, the DHCPv6 server uses the two-message exchange for prefix delegation and other configuration. If a client has included a rapid commit option in the solicit message and rapid-commit is enabled for the server, the server responds to the solicit message with a reply message. If rapid-commit is not enabled, then normal four-message exchange is done even if the clients specifies the rapid commit option.

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following is an example of the rapid-commit command:
RP/0/RP0/CPU0:router(config)# dhcp ipv6
RP/0/RP0/CPU0:router(config-dhcpv6)# interface pos 0/5/0/0 server
RP/0/RP0/CPU0:router(config-dhcpv6-if)# rapid-commit 

Related Commands

Command

Description

interface (DHCP)

Enables DHCP for IPv6 on an interface.

relay information check

To configure a Dynamic Host Configuration Protocol (DHCP) IPv4 Relay to validate the relay agent information option in forwarded BOOTREPLY messages, use the relay information check command in DHCP IPv4 relay profile configuration submode. To disable this feature, use the no form of this command.

relay information check

no relay information check

Syntax Description

This command has no keywords or arguments.

Command Default

DHCP validates the relay agent information option.

Command Modes

DHCP IPv4 relay profile configuration

Command History

Release

Modification

Release 3.7.0

This command was introduced.

Usage Guidelines

Task ID

Task ID

Operations

ip-services

read, write

basic-services

read, write

Examples

This example shows how to use the relay information check command:

RP/0/RP0/CPU0:router#config 
RP/0/RP0/CPU0:router(config)# dhcp ipv4
RP/0/RP0/CPU0:router(config-dhcpv4)# profile client relay
RP/0/RP0/CPU0:router(config-dhcpv4-relay-profile)# relay information check 

Related Commands

Command

Description

dhcp ipv4

Enables DHCP for IPv4 and enters DHCP IPv4 configuration mode.

giaddr policy

Configures how a relay agent processes BOOTREQUEST messages that already contain a nonzero giaddr attribute.

helper-address

Configures the DHCP relay agent to relay packets to a specific DHCP Server.

relay information option

Enables the system to insert a DHCP relay agent information option in forwarded BOOTREQUEST messages to a DHCP server.

relay information option allow-untrusted

Configures the DHCP component to not drop BOOTREQUEST messages that have the relay information option set and the giaddr set to zero.

Configures how a relay agent processes BOOTREQUEST messages that already contain a relay information option.

relay information option

To configure Dynamic Host Configuration Protocol (DHCP) IPv4 relay or DHCP snooping Relay to insert relay agent information option in forwarded BOOTREQUEST messages to a DHCP server, use the relay information option command in DHCP IPv4 relay profile relay configuration or DHCP IPv4 profile snoop submode. To disable inserting relay information into forwarded BOOTREQUEST messages, use the no form of this command.

relay information option

no relay information option

Syntax Description

This command has no keywords or arguments.

Command Default

None

Command Modes


            DHCP IPv4
            relay
            profile
            relay
            configuration
        

DHCP IPv4 profile snoop configuration

Command History

Release

Modification

Release 3.7.0

This command was introduced.

Usage Guidelines

The relay information option command automatically adds the circuit identifier suboption and the remote ID suboption to the DHCP relay agent information option.

The relay information option command enables a DHCP server to identify the user (for example, cable access router) sending the request and initiate appropriate action based on this information. By default, DHCP does not insert relay information.

If the information option command is enabled, DHCP snooping mode does not set the giaddr field in the DHCP packet.

The upstream DHCP server or DHCP relay interface must be configured to accept this type of packet using the relay information option allow-untrusted configuration. This configuration prevents the server or relay from dropping the DHCP message.

Task ID

Task ID

Operations

ip-services

read, write

basic-services

read, write

Examples

This example shows how to use the relay information option command:

RP/0/RP0/CPU0:router# config
RP/0/RP0/CPU0:router(config)# dhcp ipv4
RP/0/RP0/CPU0:router(config-dhcpv4)# profile client relay
RP/0/RP0/CPU0:router(config-dhcpv4-relay-profile)# relay information option

Related Commands

Command

Description

dhcp ipv4

Enables DHCP for IPv4 and enters DHCP IPv4 configuration mode.

giaddr policy

Configures how a relay agent processes BOOTREQUEST messages that already contain a nonzero giaddr attribute.

helper-address

Configures the DHCP relay agent to relay packets to a specific DHCP Server.

relay information check

Configures a DHCP server to validate the relay agent information option in forwarded BOOTREPLY messages.

relay information option allow-untrusted

Configures the DHCP component to not drop BOOTREQUEST messages that have the relay information option set and the giaddr set to zero.

Configures how a relay agent processes BOOTREQUEST messages that already contain a relay information option.

relay information option allow-untrusted

To configure the Dynamic Host Configuration Protocol (DHCP) IPv4 relay or DHCP snooping Relay not to drop discard BOOTREQUEST packets that have the relay information option set and the giaddr set to zero, use the relay information option allow-untrusted command in DHCP IPv4 relay profile configuration submode or DHCP IPv4 profile snoop configuration submode. To restore the default behavior, which is to discard the BOOTREQUEST packets that have the relay information option and set the giaddr set to zero, use the no form of this command.

relay information option allow-untrusted

no relay information option allow-untrusted

Syntax Description

This command has no keywords or arguments.

Command Default

The packet is dropped if the relay information is set and the giaddr is set to zero.

Command Modes


            DHCP IPv4
            relay
            profile
            relay
            configuration
        

DHCP IPv4 profile snoop configuration

Command History

Release

Modification

Release 3.7.0

This command was introduced.

Usage Guidelines

According to RFC 3046, relay agents (and servers) receiving a DHCP packet from an untrusted circuit with giaddr set to zero but with a relay agent information option already present in the packet shall discard the packet and increment an error count. This configuration prevents the server or relay from dropping the DHCP message.

Task ID

Task ID

Operations

ip-services

read, write

basic-services

read, write

Examples

This example shows how to use the relay information option allow-untrusted command:

RP/0/RP0/CPU0:router# config
RP/0/RP0/CPU0:router(config)# dhcp ipv4
RP/0/RP0/CPU0:router(config-dhcpv4)# profile client relay 
RP/0/RP0/CPU0:router(config-dhcpv4-relay-profile)# relay information option allow-untrusted

Related Commands

Command

Description

dhcp ipv4

Enables DHCP for IPv4 and enters DHCP IPv4 configuration mode.

giaddr policy

Configures how a relay agent processes BOOTREQUEST messages that already contain a nonzero giaddr attribute.

helper-address

Configures the DHCP relay agent to relay packets to a specific DHCP Server.

relay information check

Configures a DHCP server to validate the relay agent information option in forwarded BOOTREPLY messages.

relay information option

Enables the system to insert a DHCP relay agent information option in forwarded BOOTREQUEST messages to a DHCP server.

Configures how a relay agent processes BOOTREQUEST messages that already contain a relay information option.

relay information policy

To configure how the Dynamic Host Configuration Protocol (DHCP) IPv4 relay processes BOOTREQUEST packets that already contain a relay information option, use the relay information policy command in DHCP IPv4 relay profile configuration submode. To restore the default relay information policy, use the no form of this command.

relay information policy { drop | keep }

no relay information policy { drop | keep }

Syntax Description

drop

Directs the DHCP IPv4 Relay to discard BOOTREQUEST packets with the existing relay information option.

keep

Directs the DHCP IPv4 Relay not to discard a BOOTREQUEST packet that is received with an existing relay information option and to keep the existing relay information option value.

Command Default

The DHCP IPv4 Relay does not discard a BOOTREQUEST packet that has an existing relay information option. The option and the existing relay information option value is replaced.

Command Modes

DHCP IPv4 relay profile configuration

Command History

Release

Modification

Release 3.7.0

This command was introduced.

Usage Guidelines

Task ID

Task ID

Operations

ip-services

read, write

basic-services

read, write

Examples

This is sample output from executing the relay information policy command:

RP/0/RP0/CPU0:router# config
RP/0/RP0/CPU0:router(config)# dhcp ipv4
RP/0/RP0/CPU0:router(config-dhcpv4)# profile client relay
RP/0/RP0/CPU0:router(config-dhcpv4-relay-profile)# relay information policy keep

Related Commands

Command

Description

dhcp ipv4

Enables DHCP for IPv4 and enters DHCP IPv4 configuration mode.

Configures how a relay agent processes BOOTREQUEST messages that already contain a nonzero giaddr attribute.

helper-address

Configures the DHCP relay agent to relay packets to a specific DHCP Server.

profile (DHCP)

Configures a relay profile for the DHCP IPv4 component.

relay information check

Configures a DHCP server to validate the relay agent information option in forwarded BOOTREPLY messages.

relay information option

Enables the system to insert a DHCP relay agent information option in forwarded BOOTREQUEST messages to a DHCP server.

relay information option allow-untrusted

Configures the DHCP component to not drop BOOTREQUEST messages that have the relay information option set and the giaddr set to zero.

interface (relay profile)

Specifies a relay profile on an interface.

show dhcp ipv4 relay profile

To display Dynamic Host Configuration Protocol (DHCP) relay agent status, use the show dhcp ipv4 relay profile command in EXEC mode.

show dhcp ipv4 relay profile

Syntax Description

This command has no keywords or arguments.

Command Default

No default behavior or values

Command Modes

EXEC

Command History

Release

Modification

Release 3.7.0

This command was introduced.

Usage Guidelines

This command displays the relay profiles created for DHCP IPv4.

Task ID

Task ID

Operations

ip-services

read

Examples

The following is sample output from the show dhcp ipv4 relay profile command:

RP/0/RP0/CPU0:router# show dhcp ipv4 relay profile

DHCP IPv4 Relay Profiles
--------------------------
r1
r2

Related Commands

Command

Description

show dhcp ipv4 relay profile name

Displays Dynamic Host Configuration Protocol (DHCP) relay agent status, specific to a relay profile.

show dhcp ipv4 relay profile name

To display Dynamic Host Configuration Protocol (DHCP) relay agent status, specific to a relay profile, use the show dhcp ipv4 relay profile name command in EXEC mode.

show dhcp ipv4 relay profile [ name]

Syntax Description

name

(Optional) Name that uniquely identifies the relay profile.

Command Default

If name is not specified, displays a list of configured DHCP profile names.

No default behavior or values

Command Modes

EXEC

Command History

Release

Modification

Release 3.7.0

This command was introduced.

Usage Guidelines

Task ID

Task ID

Operations

ip-services

read

Examples

The following is sample output from the show dhcp ipv4 relay profile name command:

RP/0/RP0/CPU0:router# show dhcp ipv4 relay profile name r1

DHCP IPv4 Relay Profile r1:

Helper Addresses:
10.10.10.1, vrf default
Information Option: Disabled
Information Option Allow Untrusted: Disabled
Information Option Policy: Replace
Information Option Check: Disabled
Giaddr Policy: Keep
Broadcast-flag Policy: Ignore

VRF References:
default
Interface References:
FINT0_RP0_CPU0
MgmtEth0_RP0_CPU0_0

show dhcp ipv4 relay statistics

To display the Dynamic Host Configuration Protocol (DHCP) IPv4 relay agent packet statistics information for VPN routing and forwarding (VRF) instances, use the show dhcp ipv4 relay statistics command in EXEC mode.

show dhcp [ vrf { vrf-name | default } ] ipv4 relay statistics

Syntax Description

vrf vrf-name

(Optional) Name that uniquely identifies the VRF.

default

(Optional) Displays the relay statistics information for the default VRF.

Command Default

No default behavior or values

Command Modes

EXEC

Command History

Release

Modification

Release 3.7.0

This command was introduced.

Usage Guidelines

Task ID

Task ID

Operations

ip-services

read

Examples

The following is sample output from the show dhcp ipv4 relay statistics command when none of the optional keywords or arguments are used command :

RP/0/RP0/CPU0:router# show dhcp ipv4 relay statistics

                  Bridge              |      RX       |      TX       |       DR      |
---------------------------------------------------------------------------------------
 default                              |            0  |            0  |            0  |

The following is sample output from the show dhcp ipv4 relay statistics command using the vrf and default keywords:

RP/0/RP0/CPU0:router# show dhcp vrf default ipv4 relay statistics
Sun Apr 6 07:10:35.873 UTC

DHCP IPv4 Relay Statistics for VRF default:

     TYPE         |    RECEIVE    |    TRANSMIT   |     DROP      |
-------------------------------------------------------------------
DISCOVER          |            0  |            0  |            0  |
OFFER             |            0  |            0  |            0  |
REQUEST           |            0  |            0  |            0  |
DECLINE           |            0  |            0  |            0  |
ACK               |            0  |            0  |            0  |
NAK               |            0  |            0  |            0  |
RELEASE           |            0  |            0  |            0  |
INFORM            |            0  |            0  |            0  |
LEASEQUERY        |            0  |            0  |            0  |
LEASEUNASSIGNED   |            0  |            0  |            0  |
LEASEUNKNOWN      |            0  |            0  |            0  |
LEASEACTIVE       |            0  |            0  |            0  |
BOOTP-REQUEST     |            0  |            0  |            0  |
BOOTP-REPLY       |            0  |            0  |            0  |
BOOTP-INVALID     |            0  |            0  |            0  |

show dhcp ipv6

To display the Dynamic Host Configuration Protocol (DHCP) unique identifier (DUID) on a specified device, use the show dhcp ipv6 command in EXEC mode.

show dhcp ipv6

Command Default

No default behavior or values

Command Modes

EXEC

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Usage Guidelines

Task ID

Task ID

Operations

ip-services

read

Examples

The following is sample output from the show dhcp ipv6 command:

RP/0/RP0/CPU0:router# show dhcp ipv6 

This device's DHCPv6 unique identifier(DUID): 000300010002FCA5DC1C

show dhcp ipv6 binding

To display automatic client bindings from the Dynamic Host Configuration Protocol (DHCP) for IPv6 server binding table, use the show ipv6 dhcp binding command in EXEC mode.

show dhcp ipv6 binding [ipv6-address]

Syntax Description

ipv6-address

(optional) IPv6 address. The ipv6-address argument must be in the form documented in RFC 2373, where the address is specified in hexadecimal using 16-bit values between colons.

Command Default

No default behavior or values

Command Modes

EXEC

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Usage Guidelines

The show dhcp ipv6 binding command displays all automatic client bindings from the DHCP for IPv6 server binding table if the ipv6-address argument is not specified. When the ipv6-address argument is specified, only the binding for the specified client is displayed.

Task ID

Task ID

Operations

ip-services

read

Examples

The following is sample output from the show dhcp ipv6 binding displaying all automatic client bindings from the DHCPv6 database. The ipv6 address argument is not specified:

RP/0/RP0/CPU0:router# show dhcp ipv6 binding

  Client: FE80::202:FCFF:FEA5:DC39 (Ethernet2/1)
    DUID: 000300010002FCA5DC1C
    IA PD: IA ID 0x00040001, T1 0, T2 0
      Prefix: 3FFE:C00:C18:11::/68
              preferred lifetime 180, valid lifetime 12345
              expires at Nov 08 2002 02:24 PM (12320 seconds)
  Client: FE80::202:FCFF:FEA5:C039 (Ethernet2/1)
    DUID: 000300010002FCA5C01C
    IA PD: IA ID 0x00040001, T1 0, T2 0
      Prefix: 3FFE:C00:C18:1::/72
              preferred lifetime 240, valid lifetime 54321
              expires at Nov 09 2002 02:02 AM (54246 seconds)
      Prefix: 3FFE:C00:C18:2::/72
              preferred lifetime 300, valid lifetime 54333
              expires at Nov 09 2002 02:03 AM (54258 seconds)
      Prefix: 3FFE:C00:C18:3::/72
              preferred lifetime 280, valid lifetime 51111
              expires at Nov 09 2002 01:09 AM (51036 seconds)

This table describes the significant fields shown in the display.



Table 1  show dhcp ipv6 binding Command Field Descriptions

Field

Description

DUID

DHCP IPv6 unique identifier

IA PD

Identity Association for Prefix Delegation

Prefix

Prefixes delegated to the IAPD on the specified client

show dhcp ipv6 database

To display the Dynamic Host Configuration Protocol (DHCP) for IPv6 binding database information, use the show dhcp ipv6 database command in EXEC mode.

show dhcp ipv6 database [agent-URL]

Syntax Description

agent-URL

(Optional) Flash, NVRAM, FTP, TFTP, or Remote Copy Protocol (RCP) uniform resource locator.

Command Default

None

Command Modes

EXEC

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Usage Guidelines

Each permanent storage to which the binding database is saved is called the database agent. An agent can be configured using the dhcp ipv6 database command. Supported database agents include FTP and TFTP servers, RCP, Flash file system, and NVRAM.

The show dhcp ipv6 database command displays DHCP for IPv6 binding database agent information. If the agent-URL argument is specified, only the specified agent is displayed. If the agent-URL argument is not specified, all database agents are shown.

Task ID

Task ID Operation
ip-services

read

Examples

This is a sample output from the show dhcp ipv6 database command:

RP/0/RP0/CPU0:router# show dhcp ipv6 database

  Database agent tftp://172.19.216.133/db.tftp:
    write delay: 69 seconds, transfer timeout: 300 seconds
    last written at Jan 09 2003 01:54 PM,
        write timer expires in 56 seconds
    last read at Jan 06 2003 05:41 PM
    successful read times 1
    failed read times 0
    successful write times 3172
    failed write times 2
  Database agent nvram:/dhcpv6-binding:
    write delay: 60 seconds, transfer timeout: 300 seconds
    last written at Jan 09 2003 01:54 PM,
        write timer expires in 37 seconds
    last read at never
    successful read times 0
    failed read times 0
    successful write times 3325
    failed write times 0
  Database agent flash:/dhcpv6-db:
    write delay: 82 seconds, transfer timeout: 3 seconds
    last written at Jan 09 2003 01:54 PM,
        write timer expires in 50 seconds
    last read at never
    successful read times 0
    failed read times 0
    successful write times 2220
    failed write times 614

show dhcp ipv6 interface

To display Dynamic Host Configuration Protocol (DHCP) for IPv6 interface information, use the show dhcp ipv6 interface command in EXEC mode.

show dhcp ipv6 interface interface-type interface-instance

Syntax Description

interface-type

Interface type. For more information, use the question mark (?) online help function.

interface-instance

Either a physical interface instance or a virtual interface instance as follows:

  • Physical interface instance. Naming notation is rack/slot/module/port and a slash between values is required as part of the notation.
    • rack: Chassis number of the rack.
    • slot: Physical slot number of the modular services card or line card.
    • module: Module number. A physical layer interface module (PLIM) is always 0.
    • port: Physical port number of the interface.
    Note   

    In references to a Management Ethernet interface located on a route processor card, the physical slot number is alphanumeric (RP0 or RP1) and the module is CPU0. Example: interface MgmtEth0/RP1/CPU0/0.

  • Virtual interface instance. Number range varies depending on interface type.

For more information about the syntax for the router, use the question mark (?) online help function.

Command Default

No default behavior or values

Command Modes

EXEC

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Usage Guidelines

If no interfaces are specified, all interfaces on which DHCP for IPv6 (client or server) is enabled are shown. If an interface is specified, only information about the specified interface is displayed.

Task ID

Task ID

Operations

ip-services

read

Examples

The following is sample output from the show dhcp ipv6 interface command when an interface is not specified:

RP/0/RP0/CPU0:router
# show dhcp ipv6 interface

POS 0/5/0/0 is in server mode
  Using pool: svr-p1
  Preference value: 20
  Hint from client: ignored
  Rapid-Commit: ignored

This table describes the significant fields shown in the display.



Table 2 show dhcp ipv6 interface Command Field Descriptions

Field

Description

POS 0/5/0/0 is in server/relay mode

Displays whether the specified interface is in server or relay mode.

Using pool

Name of the pool used by the interface.

Preference value

Advertised (or default of 0) preference value for the indicated server.

Hint from client

Displays whether the allow-hint has been enabled on the interface.

Rapid-Commit

Displays whether the rapid-commit keyword has been enabled on the interface.

Related Commands

Command

Description

interface (DHCP)

Enables DHCP for IPv6 on an interface.

show dhcp ipv6 pool

To display Dynamic Host Configuration Protocol (DHCP) for IPv6 configuration information pool information, use the show ipv6 dhcp pool command in EXEC mode.

show dhcp ipv6 pool [pool-name]

Syntax Description

pool-name

(Optional) User-defined name for the local prefix pool. The pool name can be a symbolic string (such as "Engineering") or an integer (such as 0).

Command Default

No default behavior or values

Command Modes

EXEC

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Usage Guidelines

Use the dhcp ipv6 pool command to create a configuration information pool, and use the dhcp ipv6 server command to associate the configuration information pool with a server on an interface.

The show dhcp ipv6 pool command displays DHCP for IPv6 configuration information pool information. If the poolname argument is specified, only information on the specified pool is displayed. If the poolname argument is not specified, all pools are shown.

Task ID

Task ID

Operations

ip-services

read

Examples

The following is sample output from the show dhcp ipv6 pool command. If pool-name is not specified, all pools are shown; otherwise, only the named pool is displayed.

RP/0/RP0/CPU0:router# show dhcp ipv6 pool

  DHCPv6 pool: svr-p1
    Static bindings:
      Binding for client 000300010002FCA5C01C
        IA PD: IA ID 00040002, 
          Prefix: 3FFE:C00:C18:3::/72
                  preferred lifetime 604800, valid lifetime 2592000
        IA PD: IA ID not specified; being used by 00040001
          Prefix: 3FFE:C00:C18:1::/72
                  preferred lifetime 240, valid lifetime 54321
          Prefix: 3FFE:C00:C18:2::/72
                  preferred lifetime 300, valid lifetime 54333
          Prefix: 3FFE:C00:C18:3::/72
                  preferred lifetime 280, valid lifetime 51111
DNS server: 1001::1
    DNS server: 1001::2
    Domain name: domain1.net
    Domain name: domain2.net
    Domain name: domain3.net
   Active clients: 2

This table describes the significant fields shown in the display.



Table 3 show ipv6 dhcp pool Command Field Descriptions

Field

Description

DHCPv6 pool

The name of the pool.

IA PD

Identity association for prefix delegation (IA PD), which is a collection of prefixes assigned to a client.

Prefix

Prefixes to be delegated to the indicated IAPD on the specified client.

preferred lifetime, valid lifetime

Lifetimes associated with the prefix statically assigned to the specified client.

DNS server

IPv6 addresses of the DNS servers.

Domain name

Displays the DNS domain search list.

Active clients

Total number of active clients.

sip address

To configure a Session Initiation Protocol (SIP) server IPv6 address to be returned in the SIP server's IPv6 address list option to clients, use the sip address command in Dynamic Host Configuration Protocol (DHCP) IPv6 pool configuration mode. To disable this feature, use the no form of this command.

sip address ipv6 address

no sip address ipv6 address

Syntax Description

ipv6-address

IPv6 address. The ipv6-address argument must be in the form documented in RFC 2373, where the address is specified in hexadecimal using 16-bit values between colons.

Command Default

No default behavior or values

Command Modes

DHCP IPv6 pool configuration

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Usage Guidelines

For the Dynamic Host Configuration Protocol (DHCP) for IPv6 server to obtain prefixes from RADIUS servers, the user must also configure the authorization, authentication, and accounting (AAA) client and PPP on the router. For information on how to configure the AAA client and PPP, see the “Implementing ADSL and Deploying Dial Access for IPv6” module of the Cisco IOS XR System Security Command Reference.

The sip address command configures a SIP server IPv6 address to be returned in the SIP server's IPv6 address list option to clients. To configure multiple SIP server addresses, issue this command multiple times. The new addresses do not overwrite old ones.

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following example shows how to configure the SIP address using the sip-address command:

RP/0/RP0/CPU0:router(config)# dhcp ipv6 pool pool1
RP/0/RP0/CPU0:router(config-dhcpv6-pool)# sip address 10:10::10

Related Commands

Command

Description

pool (DHCP IPv6)

Configures a Dynamic Host Configuration Protocol (DHCP) for the IPv6 server configuration information pool and enters DHCP for IPv6 pool configuration mode.

sip domain-name

To configure a Session Initiation Protocol (SIP) server domain name to be returned in the SIP server's domain name list option to clients, use the sip domain-name command in Dynamic Host Configuration Protocol (DHCP) IPv6 pool configuration mode. To disable this feature, use the no form of this command.

sip domain-name domain-name

no sip domain-name domain-name

Syntax Description

domain-name

Domain name for a DHCP for IPv6 client.

Command Default

No default behavior or values

Command Modes

DHCP IPv6 pool configuration

Command History

Release

Modification

Release 3.4.0

This command was introduced.

Usage Guidelines

For the Dynamic Host Configuration Protocol (DHCP) for IPv6 server to obtain prefixes from RADIUS servers, the user must also configure the authorization, authentication, and accounting (AAA) client and PPP on the router. For information on how to configure the AAA client and PPP, see the “Implementing ADSL and Deploying Dial Access for IPv6” module of the Cisco IOS XR System Security Command Reference.

The sip domain-name command configures a SIP server domain name to be returned in the SIP server's domain name list option to clients. To configure multiple SIP server domain names, issue this command multiple times. The new domain names do not overwrite old ones.

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following example shows how to configure the SIP address using the sip domain-name command:

RP/0/RP0/CPU0:router(config)# dhcp ipv6 pool pool1
RP/0/RP0/CPU0:router(config-dhcpv6-pool)# sip domain-name domain1.com

Related Commands

Command

Description

pool (DHCP IPv6)

Configures a Dynamic Host Configuration Protocol (DHCP) for the IPv6 server configuration information pool and enters DHCP for IPv6 pool configuration mode.

vrf (relay profile)

To configure a relay profile on a VPN routing and forwarding (VRF) instance, use the vrf (relay profile) command in Dynamic Host Configuration Protocol (DHCP) IPv4 configuration mode. To disable this feature, use the no form of this command.

vrf { vrf-name { relay } profile-name | default | all }

no vrf { vrf-name { relay } profile-name | default | all }

Syntax Description

vrf-name

User-defined name for the VRF.

relay

Specifies a relay profile.

profile-name

Specifies a name for the profile.

default

Specifies a profile for the default VRF.

all

Specifies a profile for all VRFs.

Command Default

If default is selected, then the configuration defaults to VRF.

Command Modes

DHCP IPv4 configuration

Command History

Release

Modification

Release 3.7.0

This command was introduced.

Usage Guidelines

To use this command, you must be in a user group associated with a task group that includes the proper task IDs. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Task ID

Task ID

Operations

ip-services

read, write

Examples

The following example shows how to set the relay profile for all VRFs:

RP/0/RP0/CPU0:router# config
RP/0/RP0/CPU0:router(config)# dhcp ipv4
RP/0/RP0/CPU0:router(config-dhcpv4)# vrf all

Related Commands

Command

Description

dhcp ipv4

Enables DHCP for IPv4 and enters DHCP IPv4 configuration mode.

Configures how a relay agent processes BOOTREQUEST messages that already contain a nonzero giaddr attribute.

Configures the DHCP relay agent to relay packets to a specific DHCP Server.

relay information check

Configures a DHCP server to validate the relay agent information option in forwarded BOOTREPLY messages.

relay information option

Enables the system to insert a DHCP relay agent information option in forwarded BOOTREQUEST messages to a DHCP server.

relay information option allow-untrusted

Configures the DHCP component to not drop BOOTREQUEST messages that have the relay information option set and the giaddr set to zero.

Configures how a relay agent processes BOOTREQUEST messages that already contain a relay information option.