IP Addresses and Services Configuration Guide for Cisco 8000 Series Routers, IOS XR Releases

PDF

IP Addresses and Services Configuration Guide for Cisco 8000 Series Routers, IOS XR Releases

Configure the DHCP relay agent

Updated: August 12, 2026

Want to summarize with AI?

Log in

This topic describes how to configure and enable the DHCP relay agent on the Cisco 8000 Series Router.

Configure a DHCP relay profile and attach it to a BVI interface to forward DHCP packets between clients and DHCP servers.

Procedure

  1. Enter the global configuration mode, and enter the DHCP IPv4 configuration submode.

    Example:

    Router# configure
Router(config)# dhcp ipv4

  2. Enable the DHCP relay profile.

    Example:

    Router(config-dhcpv4)# profile r1 relay

  3. Configure VRF addresses for forwarding UDP broadcasts, including DHCP.

    Example:

    Router(config-dhcpv4-relay-profile)# helper-address vrf A 10.10.7.1 giaddr 10.10.7.2
Router(config-dhcpv4-relay-profile)# broadcast-flag policy check

  4. Insert the DHCP relay agent information option (option-82 field) in forwarded BOOTREQUEST messages to a DHCP server.

    Example:

    Router(config-dhcpv4-relay-profile)# relay information option vpn
Router(config-dhcpv4-relay-profile)# relay information option vpn-mode rfc

  5. (Optional) Configure the DHCP IPv4 Relay not to discard BOOTREQUEST packets that have an existing relay information option and the giaddr set to zero.

    Example:

    Router(config-dhcpv4-relay-profile)# relay information option allow-untrusted
Router(config-dhcpv4-relay-profile)# exit

  6. Configure DHCP relay on a BVI interface and commit the configuration.

    Example:

    Router(config-dhcpv4)# interface BVI 1 relay profile r1
Router(config-dhcpv4)# commit