12.1. DHCPv6 Snooping Commands

Command Purpose

Use the clear dhcpv6 snooping bindings learning privileged EXEC command on the switch to clear the dynamic DHCPv6 binding items.

Prerequisites

Command Syntax

clear dhcpv6 snooping bindings ( learning | manual ) ( ipv6 IP-ADDRESS | mac MAC-ADDRESS | vlan VLAN-ID | interface IFNAME | )

Command Mode

Privileged EXEC

Default

No default is defined.

Usage

This command is used to clear DHCPv6 snooping binding.

Examples

This example shows how to clear all DHCPv6 snooping binding learning items:

Switch# clear dhcpv6 snooping bindings learning

Related Commands

show dhcpv6 snooping binding

Command Purpose

Use the clear dhcpv6 snooping statistics privileged EXEC command on the switch to clear the DHCPv6 snooping statistics counters.

Prerequisites

Command Syntax

clear dhcpv6 snooping statistics

Command Mode

Privileged EXEC

Default

No default is defined.

Usage

This command is used to clear DHCPv6 snooping statistics.

Examples

This example shows how to clear the DHCPv6 snooping statistics counters:

Switch# clear dhcpv6 snooping statistics

Related Commands

show dhcpv6 snooping statistics

Command Purpose

Use the dhcpv6 snooping Global Config command on the switch to globally enable DHCPv6 snooping.

Use the no form of this command to return to the default setting.

Prerequisites

Command Syntax

dhcpv6 snooping

no dhcpv6 snooping

Command Mode

Global Config

Default

DHCPv6 snooping is disabled.

Usage

For any DHCPv6 snooping configuration to take effect, you must globally enable DHCPv6 snooping. DHCPv6 snooping is not active until you enable snooping on a VLAN by using the dhcpv6 snooping vlan global configuration command.

Examples

This example shows how to enable DHCPv6 snooping:

Switch# configure terminal
Switch(config)# dhcpv6 snooping

You can verify your settings by entering the show dhcpv6 snooping config privileged EXEC command:

Related Commands

dhcpv6 snooping vlan

show dhcpv6 snooping config

Command Purpose

Use the dhcpv6 snooping binding Global Config command on the switch to configure the DHCPv6 snooping binding database and to add binding entries to the database.

Prerequisites

Command Syntax

dhcpv6 snooping binding mac MAC-ADDRESS vlan VLAN-ID ipv6 IP-ADDRESS interface IFNAME expiry SECONDS

no dhcpv6 snooping bindings ( ipv6 IP-ADDRESS | mac MAC-ADDRESS | vlan VLAN-ID | interface IFNAME | )

Command Mode

Global Config

Default

No default database is defined.

Usage

Use this command when you are testing or debugging the switch.

In the DHCPv6 snooping binding database, each database entry, also referred to a binding, has an IP address, an associated MAC address, the lease time, the interface to which the binding applies, and the VLAN to which the interface belongs.

Use the show dhcpv6 snooping binding privileged EXEC command to display the configured bindings.

Examples

This example shows how to generate a DHCPv6 binding with an expiration time of 1000 seconds on a port in VLAN 1:

Switch# configure terminal
Switch(config)# dhcpv6 snooping binding mac 0058.3f0c.01ef vlan 1 ipv6 2001:1::1 interface eth-0-1 expiry 1000

Related Commands

show dhcpv6 snooping binding

Command Purpose

Use the dhcpv6 snooping database Global Config command on the switch to configure the DHCPv6 snooping binding database agent. Use the no form of this command to reset the write-delay value.

Prerequisites

Command Syntax

dhcpv6 snooping database auto-save interval SECONDS

Command Mode

Global Config

Default

Default interval is 600 seconds.

Usage

The DHCPv6 snooping database is save as flash:/dhcpv6snooping.

Examples

The following is sample output from the dhcpv6 snooping database command:

Switch# configure terminal
Switch(config)# dhcpv6 snooping database auto-save interval 120

Related Commands

dhcpv6 snooping

dhcpv6 snooping binding

Command Purpose

Use the dhcpv6 snooping remote-id format Global Config command on the switch to configure the format of dhcpv6 snooping remote-id. Use the no form of this command to set the format of dhcpv6 snooping remote-id to default format.

Prerequisites

Command Syntax

dhcpv6 snooping remote-id format { vlan | ifname | duid }

no dhcpv6 snooping remote-id format

Command Mode

Global Config

Default

Default format is duid::ifname

Usage

The format of remote-id can be a combination of vlan, interface name, DUID. This command specifies the existing keywords in the combination.

Examples

The following example shows how to specify the format of remote-id:

Switch# configure terminal
Switch(config)# dhcpv6 snooping remote-id format duid vlan ifname

Related Commands

dhcpv6 snooping remote-id option

Command Purpose

Use the dhcpv6 snooping remote-id option Global Config command on the switch to globally enable insert dhcpv6 snooping remote-id. Use the no form of this command to globally disable insert dhcpv6 snooping remote-id.

Prerequisites

Command Syntax

dhcpv6 snooping remote-id option

no dhcpv6 snooping remote-id option

Command Mode

Global Config

Default

Insert remote-id is disabled

Usage

None

Examples

The following example shows how to enable remote-id option:

Switch# configure terminal
Switch(config)# dhcpv6 snooping remote-id option

Related Commands

dhcpv6 snooping remote-id format

Command Purpose

Use the dhcpv6 snooping trust interface configuration command on the switch to configure a port as trusted for DHCPv6 snooping purposes.

Use the no form of this command to return to the default setting.

Prerequisites

Command Syntax

dhcpv6 snooping trust

no dhcpv6 snooping trust

Command Mode

Interface Configuration

Default

DHCPv6 snooping trust is disabled.

Usage

Configure as trusted ports those that are connected to a DHCPv6 server or to other switches or routers. Configure as entrusted ports those that are connected to DHCPv6 clients.

Examples

This example shows how to enable DHCPv6 snooping trust on a port:

Switch# configure terminal
Switch(config)# interface eth-0-1
Switch(config-if)# dhcpv6 snooping trust

Related Commands

show dhcpv6 snooping trusted-sources

Command Purpose

Use the dhcpv6 snooping vlan Global Config command on the switch to enable DHCPv6 snooping on a VLAN. Use the no form of this command to return to the default setting.

Prerequisites

Command Syntax

dhcpv6 snooping vlan VLAN-RANGE

no dhcpv6 snooping vlan VLAN-RANGE

Command Mode

Global Config

Default

DHCPv6 snooping is disabled on all VLANs.

Usage

You can enter a single VLAN ID identified by VLAN ID number, a series of VLAN IDs separated by commas, a range of VLAN IDs separated by hyphens, or a range of VLAN IDs separated by entering the starting and ending VLAN IDs separated by a space.

You must first globally enable DHCPv6 snooping before enabling DHCPv6 snooping on a VLAN.

Examples

This example shows how to enable DHCPv6 snooping on VLAN 10:

Switch# configure terminal
Switch(config)# dhcpv6 snooping vlan 10

Related Commands

show dhcpv6 snooping config

Command Purpose

Use this command to turn on the debug switches of dhcpv6 snooping module.

To restore the default, use the no form of this command

Prerequisites

Command Syntax

debug dhcpv6 snooping ( events | error | dump | packet | all )

no debug dhcpv6 snooping ( events | error | dump | packet | all )

Command Mode

Privileged EXEC

Default

None

Usage

Use command “terminal monitor” to make debug messages print on the VTY immediately.

Use command “show logging buffer” to check the debug messages in the logging buffer.

Examples

The following is sample to open dhcpv6 snooping debug switches:

Switch# debug dhcpv6 snooping all

Related Commands

terminal monitor

show logging buffer

Command Purpose

Use the show dhcpv6 snooping binding privileged EXEC command to display the DHCPv6 snooping binding database and configuration information for all interfaces on a switch.

Prerequisites

Command Syntax

show dhcpv6 snooping binding (（all | manual | learning ）( ipv4 IP-ADDRESS | mac MAC-ADDRESS | vlan VLAN-ID | interface IFNAME | ) summary | )

Command Mode

Privileged EXEC

Default

None

Usage

If DHCPv6 snooping is enabled and an interface changes to the down state, the switch does not delete the statically configured bindings.

Examples

The following is sample output from the show dhcpv6 snooping binding command:

Switch# show dhcpv6 snooping binding all

DHCPv6 snooping binding table:
VLAN MAC Address    Interface  Lease(s)   IPv6 Address
============================================================
1    0001.0001.0001 eth-0-2    static     1:1::1:1
Switch# show dhcpv6 snooping binding summary
Total 1 DHCPv6 snooping binding entries
    0 learning entry, 1 configured entry

Related Commands

dhcpv6 snooping binding

Command Purpose

Use the show dhcpv6 snooping privileged EXEC command to display the DHCPv6 snooping configuration.

Prerequisites

Command Syntax

show dhcpv6 snooping config

Command Mode

Privileged EXEC

Default

None

Usage

This command is used to display the configuration of DHCPv6 snooping.

Examples

The following is sample output from the show dhcpv6 snooping config command:

Switch# show dhcpv6 snooping config

dhcpv6 snooping service: enabled
dhcpv6 snooping switch: enabled
dhcpv6 snooping vlan 3

Related Commands

dhcpv6 snooping

dhcpv6 snooping vlan

Command Purpose

Use the show dhcpv6 snooping trusted-sources privileged EXEC command to display the DHCPv6 snooping trusted interface.

Prerequisites

Command Syntax

show dhcpv6 snooping trusted-sources

Command Mode

Privileged EXEC

Default

None

Usage

This command is used to display the trusted interface of DHCPv6 snooping.

Examples

The following is sample output from the show dhcpv6 snooping trusted-sources command:

Switch# show dhcpv6 snooping trusted-source

List of DHCPv6 snooping trusted interface(s):
============================================================
eth-0-20

Related Commands

dhcpv6 snooping trust

Command Purpose

Use the show dhcpv6 snooping statistics privileged EXEC command to display DHCPv6 snooping statistics.

Prerequisites

Command Syntax

show dhcpv6 snooping statistics

Command Mode

Privileged EXEC

Default

None

Usage

This command is used to display the statistics of DHCPv6 snooping.

Examples

The following is sample output from the show dhcpv6 snooping statistics command:

Switch# show dhcpv6 snooping statistics

DHCPv6 snooping statistics:
============================================================
DHCPv6 packets                            137
Packets forwarded                         137
Packets invalid                           0
Packets dropped                           0

Related Commands

clear dhcpv6 snooping statistics