Cisco Catalyst 9800 Series Wireless Controller Software Configuration Guide, Cisco IOS XE 26.1.x

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Cisco Catalyst 9800 Series Wireless Controller Software Configuration Guide, Cisco IOS XE 26.1.x

DHCP and NAT functionality on root AP (RAP)

Updated: April 10, 2026

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Describes integrated DHCP server and NAT functions provided by root APs, including operational processes, configuration steps, and verification commands for network service delivery.

DHCP and NAT functionality is a wireless network feature that

  • assigns private IPv4 addresses to client devices using DHCP

  • translates these private addresses to public addresses for network access with NAT, and

  • enables root APs (RAPs) to provide seamless connectivity for clients in a mesh network.

The APs associated with a mesh network can play one of the two roles:

  • Root Access Point (RAP) — An AP can be a root AP for multiple mesh networks.

  • Mesh Access Point (MAP) — An AP can be a mesh AP for only one mesh network at a time.

Note

This feature is applicable for Cisco Aironet 1542 series outdoor APs.

How DHCP and NAT functionalities work on root AP - IPv4 scenario

In wireless mesh networking, root APs (RAPs) can be enabled to provide both DHCP (Dynamic Host Configuration Protocol) and NAT (Network Address Translation) functionalities. This feature enables the controller to send a TLV to RAP when a new RAP joins the controller.

Summary

RAPs use integrated DHCP and NAT functionalities to assign private IPv4 addresses to wireless clients and provide secure, translated access to external networks. The process orchestrates communication between the network controller, RAP, and client device.

Workflow

The workflow consists of these steps:

  1. The controller sends a TLV to configure the RAP with DHCP and NAT functionalities when a RAP joins the network.
  2. A client device associates to the RAP’s SSID.
  3. The RAP assigns a private IPv4 address to the client using its DHCP functionality.
  4. The RAP applies NAT to translate the client’s private address, enabling secure access to external networks.

Result

Wireless clients that connect to RAPs receive private IPv4 addresses and can securely access external networks using DHCP and NAT services managed by the RAP.

Configure DHCP server on root AP (CLI)

Configure a DHCP server on the root AP.

Procedure

1.

Enter global configuration mode.

Example:

Device# configure terminal
2.

Configure an AP profile.

Example:

Device(config)# ap profile ap-profile-name
3.

Configure the DHCP server on the root AP.

Example:

Device(config-ap-profile)# dhcp-server
4.

Exit the configuration mode.

Example:

Device(config-ap-profile)# end

The system saves the configuration, exits configuration mode, and returns to privileged EXEC mode.

The root AP is now configured as a DHCP server and assigns IP addresses to associated clients.

DHCP server for root AP configuration verification

To verify the DHCP server for root AP configuration, use this command:

Device# show ap config general
Cisco AP Name   : AP4C77.6DF2.D588
=================================================
<SNIP>
Dhcp Server                                     : Enabled