Configure DHCP Relay on an IP Interface

Use this procedure to view or modify configuration information about the DHCP relay on IP interfaces.

Procedure

  1. In the navigation tree, expand Configuration > IP.
  2. Select DHCP Relay.
  3. Select the Interfaces tab.
  4. To change the configuration information, select the field in the row for the required interface, and then type or select a new value.
  5. Select Apply.

Interfaces Field Descriptions

Use the data in the following table to use the Interfaces tab.

Variable

Value

IfIndex

Display a read-only interface number that represents a physical interface, or the VLAN logical interface.

MaxHop

Specifies the maximum number of hops a 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

Specifies if DHCP Reply packets can be sent as a broadcast to the DHCP client. The default is false.

CircuitId

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

RemoteId

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

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

Enables DHCP Smart Relay on a VLAN interface in one of the following modes:

  • 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.

By default, Smart Relay is disabled.
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