Configure BootP/DHCP on a VLAN or VRF Instance

Use the DHCP Relay tab to configure the DHCP behavior on a VLAN.

Before you begin

  • You must enable IP Routing on the interface.

  • To perform this procedure on a non-default VRF, you must first change the VRF instance. For information about how to use EDM for a non-default VRF, see Select and Launch a VRF Context View. All parameters might not be available in non-default VRFs.

About this task

Procedure

  1. In the navigation pane, expand Configuration > VLAN.
  2. Select VLANs.
  3. Select the Basic tab.
  4. Select a VLAN.
  5. Select IP.
  6. Select the DHCP Relay tab.
  7. Select Enable.
  8. Optional: Configure the parameters as required.
  9. Select Apply.

DHCP Relay Field Descriptions

Use the data in the following table to use the DHCP Relay tab.

Variable

Value

Enable

Enables DHCP Relay on the VLAN. The default is disable.

MaxHop

Specifies the maximum number of hops a BootP/DHCP packet can take from the DHCP client to the DHCP server. The default is 4.

MinSec

Specifies the minimum number of seconds to wait between receiving a DHCP packet and forwarding the DHCP packet to the DHCP server. A value of 0 indicates that forwarding is done immediately. The default value is 0.

Mode

Specifies the type of DHCP packet required. The options are:

  • bootp

  • dhcp

  • both

The default is both.

AlwaysBroadcast

When enabled, the DHCP Reply packets are sent as a broadcast to the DHCP client. The default is disable.

CircuitId

Specifies whether DHCP Relay inserted the option 82 circuit ID information into the DHCP packets before sending the DHCP packets to the DHCP server. The default is disable.

RemoteId

Specifies whether DHCP Relay inserted the option 82 remote ID information into the DHCP packets before sending the DHCP packets to the DHCP server. The default is disable.

Trusted

Specifies if DHCP packets come through a trusted DHCP circuit. Only packets with GIADDR configured to 0 and containing option 82 are forwarded if the circuit is trusted. The default value is false.

SmartRelayMode

Specifies one of the following DHCP Smart Relay modes:

  • disabled

  • parallel - the relay agent makes multiple copies of DHCP requests and inserts each IP address of the client- facing interface (VLAN or VRRP) as the gateway address in each copy of the request. The switch simultaneously relays multiple packets to the DHCP server, assigning each packet the correct IP address in the correct subnet.

  • sequential - the relay agent forwards received DHCP packets from all IP addresses on the VLAN or VRRP interface one at a time, starting with the primary address and continuing with each secondary address.

The default is disabled.
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