DHCP L2 Relay Agent Comamnds

You can enable the switch to operate as a DHCP Layer 2 relay agent to relay DHCP requests from clients to a Layer 3 relay agent or server. The Circuit ID and Remote ID can be added to DHCP requests relayed from clients to a DHCP server. This information is included in DHCP Option 82, as specified in sections 3.1 and 3.2 of RFC3046.

dhcp l2relay

This command enables the DHCP Layer 2 Relay agent for an interface a range of interfaces in, or all interfaces. The subsequent commands mentioned in this section can only be used when the DHCP L2 relay is enabled.

• Format: dhcp l2relay
• Mode:
  • Global Config
  • Interface Config

no dhcp l2relay

This command disables DHCP Layer 2 relay agent for an interface or range of interfaces.

• Format: no dhcp l2relay
• Mode:
  • Global Config
  • Interface Config

dhcp l2relay circuit-id subscription-name

This command sets the Option-82 Circuit ID for a given service subscription identified by <subscription-string> on a given interface. The no dhcp l2relay is a character string which needs to be matched with a configured DOT1AD subscription string for correct operation. When circuit-id is enabled using this command, all Client DHCP requests that fall under this service subscription are added with Option-82 circuit- id as the incoming interface number.

• Default: disabled
• Format: dhcp l2relay circuit-id subscription-name subscription-string
• Mode: Interface Config

no dhcp l2relay circuit-id subscription-name

This command resets the Option-82 Circuit ID for a given service subscription identified by <subscription-string> on a given interface. The <subscription-string> is a character string which needs to be matched with a configured DOT1AD subscription string for correct operation. When circuit-id is disabled using this command, all Client DHCP requests that fall under this service subscription are no longer added with Option- 82 circuit-id.

• Format: no dhcp l2relay circuit-id subscription-name subscription-string
• Mode: Interface Config

dhcp l2relay circuit-id vlan

This parameter sets the DHCP Option-82 Circuit ID for a VLAN. When enabled, the interface number is added as the Circuit ID in DHCP option 82.

• Format: dhcp l2relay circuit-id vlan <vlan-list>
• Mode: Global Config
• vlan–list: The VLAN ID. The range is 1–4093. Separate non-consecutive IDs with a comma (,) no spaces and no zeros in between the range. Use a dash (–) for the range.

no dhcp l2relay circuit-id vlan

This parameter clears the DHCP Option-82 Circuit ID for a VLAN.

• Format: no dhcp l2relay circuit-id vlan <vlan-list>
• Mode: Global Config

dhcp l2relay remote-id subscription-name

This command sets the Option-82 Remote-ID string for a given service subscription identified by <subscription-string> on a given interface or range of interfaces. The subscription-string is a character string which needs to be matched with a configured DOT1AD subscription string for correct operation. The remoteid-string is a character string. When remote-id string is set using this command, all Client DHCP requests that fall under this service subscription are added with Option-82 Remote-id as the configured remote-id string.

• Default: empty string
• Format:dhcp l2relay remote-id <remoteid-string> subscription-name <subscription-string>
• Mode: Interface Config

no dhcp l2relay remote-id subscription-name

This command resets the Option-82 Remote-ID string for a given service subscription identified by subscription-string on a given interface. The subscription-string is a character string which needs to be matched with a configured DOT1AD subscription string for correct operation. When remote-id string is reset using this command, the Client DHCP requests that fall under this service subscription are not added with Option-82 Remote-id.

• Format: no dhcp l2relay remote-id <remoteid-string> subscription-name <subscription-string>
• Mode: Interface Config

dhcp l2relay remote-id vlan

This parameter sets the DHCP Option-82 Remote ID for a VLAN and subscribed service (based on subscription- name).

• Format: dhcp l2relay remote-id <remote-id-string> vlan <vlan-list>
• Mode: Global Config
• vlan–list: The VLAN ID. The range is 1–4093. Separate non-consecutive IDs with a comma (,) no spaces and no zeros in between the range. Use a dash (–) for the range.

no dhcp l2relay remote-id vlan

This parameter clears the DHCP Option-82 Remote ID for a VLAN and subscribed service (based on subscription-name).

• Format: no dhcp l2relay remote-id vlan <vlan-list>
• Mode: Global Config

dhcp l2relay subscription-name

This command enables relaying DHCP packets on an interface or range of interfaces that fall under the specified service subscription. The subscription-string is a character string that needs to be matched with configured DOT1AD subscription string for correct operation.

• Default: disabled (i.e. no DHCP packets are relayed)
• Format: dhcp l2relay subscription-name <subscription-string>
• Mode: Interface Config

no dhcp l2relay subscription-name

This command disables relaying DHCP packets that fall under the specified service subscription. The subscription-string is a character string that needs to be matched with configured DOT1AD subscription string for correct operation.

• Format: no dhcp l2relay subscription-name <subscription-string>
• Mode: Interface Config

dhcp l2relay trust

Use this command to configure an interface or range of interfaces as trusted for Option-82 reception.

• Default: untrusted
• Format: dhcp l2relay trust
• Mode: Interface Config

no dhcp l2relay trust

Use this command to configure an interface to the default untrusted for Option-82 reception.

• Format: no dhcp l2relay trust
• Mode: Interface Config

dhcp l2relay vlan

Use this command to enable the DHCP L2 Relay agent for a set of VLANs. All DHCP packets which arrive on interfaces in the configured VLAN are subject to L2 Relay processing.

• Default: disable
• Format: dhcp l2relay vlan <vlan-list>
• Mode: Global Config
• vlan–list: The VLAN ID. The range is 1–4093. Separate non-consecutive IDs with a comma (,) no spaces and no zeros in between the range. Use a dash (–) for the range.

no dhcp l2relay vlan

Use this command to disable the DHCP L2 Relay agent for a set of VLANs.

• Format: no dhcp l2relay vlan <vlan-list>
• Mode: Global Config

show dhcp l2relay all

This command displays the summary of DHCP L2 Relay configuration.

• Format: show dhcp l2relay all
• Mode: Privileged EXEC

show dhcp l2relay circuit-id vlan

This command displays DHCP circuit-id vlan configuration.

• Format: show dhcp l2relay circuit-id vlan <vlan-list>
• Mode: Privileged EXEC

The display parameters for above command are:

• vlan-list: Enter VLAN IDs in the range 1–4093. Use a dash (–) to specify a range or a comma (,) to separate VLAN IDs in a list. Spaces and zeros are not permitted.

show dhcp l2relay interface

This command displays DHCP L2 relay configuration specific to interfaces.

• Format: show dhcp l2relay interface {all | <interface-num>}
• Mode: Privileged EXEC

show dhcp l2relay remote-id vlan

This command displays DHCP Remote-id vlan configuration.

• Format: show dhcp l2relay remote-id vlan <vlan-list>
• Mode: Privileged EXEC

The display parameters for above command are:

• vlan-list Enter VLAN IDs in the range 1–4093. Use a dash (–) to specify a range or a comma (,) to separate VLAN IDs in a list. Spaces and zeros are not permitted.

show dhcp l2relay stats interface

This command displays statistics specific to DHCP L2 Relay configured interface.

• Format: show dhcp l2relay stats interface {all | <interface-num>}
• Mode: Privileged EXEC

show dhcp l2relay subscription interface

This command displays DHCP L2 Relay configuration specific to a service subscription on an interface.

• Format: show dhcp l2relay subscription interface {all|<interface-num>}
• Mode: Privileged EXEC

show dhcp l2relay agent-option vlan

This command displays the DHCP L2 Relay Option-82 configuration specific to VLAN.

• Format: show dhcp l2relay agent-option vlan <vlan-range>
• Mode: Privileged EXEC

show dhcp l2relay vlan

This command displays DHCP vlan configuration.

• Format: show dhcp l2relay vlan <vlan-list>
• Mode: Privileged EXEC

The display parameters for above command are:

• vlan-list: Enter VLAN IDs in the range 1–4093. Use a dash (–) to specify a range or a comma (,) to separate VLAN IDs in a list. Spaces and zeros are not permitted.

clear dhcp l2relay statistics interface

Use this command to reset the DHCP L2 relay counters to zero. Specify the port with the counters to clear, or use the all keyword to clear the counters on all ports.

• Format: clear dhcp l2relay statistics interface {<unit/slot/port> | all}
• Mode: Privileged EXEC