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

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

Introduction to DHCP relay

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This topic describes the DHCP relay agent on the Cisco 8000 Series Router, which forwards DHCP packets between clients and servers that do not reside on a shared physical subnet.


A DHCP relay agent is a host that

  • forwards DHCP packets between clients and servers that do not reside on a shared physical subnet, and

  • differs from a normal IP router because it processes and forwards DHCP messages instead of transparently switching IP datagrams between networks.

Table 1. Feature History Table

Feature Name

Release Information

Feature Description

Extending DHCP Relay agent support

Release 26.3.1

Introduced in this release on: Modular Systems (8800 [LC ASIC: K100])(select variants only*)

*This feature is supported on Cisco 88-LC1-48Y8F-EM line cards.

Extending DHCP Relay agent support

Release 26.1.1

Introduced in this release on: Centralized Systems (8400 [ASIC: K100])(select variants only*)

*This feature is now supported on Cisco 8404-SYS-D routers.

Extending DHCP Relay agent support

Release 25.4.1

Introduced in this release on: Fixed Systems (8010 [ASIC: A100], 8700 [ASIC: K100])(select variants only*)

* This feature is supported on:

  • 8712-MOD-M

  • 8711-48Z-M

  • 8011-32Y8L2H2FH

  • 8011-12G12X4Y-A/D

Extending DHCP Relay agent support

Release 25.2.1

Introduced in this release on: Fixed Systems ((8010 [ASIC: A100], 8200 [ASIC: P100]), 8700 [ASIC: P100])(select variants only*); Modular Systems (8800 [LC ASIC: P100])(select variants only*)

* This feature is supported on:

  • 8011-4G24Y4H-I

  • 8212-48FH-M

  • 8711-32FH-M

  • 88-LC1-36EH

Extending DHCP Relay agent support

Release 25.1.1

Introduced in this release on: Modular Systems (8800 [LC ASIC: P100]) (select variants only*)

This release introduces support for DHCP Relay Agent and DHCPv6 Relay Over BVI for IANA Address Allocation to Cisco Silicon One P100 ASIC-based systems.

The feature, enabled by default, efficiently allocates IP addresses from a centralized DHCP server to clients across multiple subnets. It ensures that devices can receive IP addresses even when they are not on the same local network as the DHCP server.

*The feature is supported on:

  • 88-LC1-52Y8H-EM

  • 88-LC1-12TH24FH-E