Configuring DHCP Proxy
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Configuring DHCP ProxyConfiguring DHCP Proxy
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Configuring DHCP Proxy

Information About Configuring DHCP Proxy

When DHCP proxy is enabled on the controller, the controller unicasts DHCP requests from the client to the configured servers. Consequently, at least one DHCP server must be configured on either the interface associated with the WLAN or the WLAN itself.

When DHCP proxy is disabled on the controller, those DHCP packets transmitted to and from the clients are bridged by the controller without any modification to the IP portion of the packet. Packets received from the client are removed from the CAPWAP tunnel and transmitted on the upstream VLAN. DHCP packets directed to the client are received on the upstream VLAN, converted to 802.11, and transmitted through a CAPWAP tunnel toward the client. As a result, the internal DHCP server cannot be used when DHCP proxy is disabled. The ability to disable DHCP proxy allows organizations to use DHCP servers that do not support Cisco’s native proxy mode of operation. It should be disabled only when required by the existing infrastructure.

Guidelines and Limitations

  • DHCP proxy is enabled by default.
  • DHCP proxy must be enabled in order for DHCP option 82 to operate correctly.
  • All controllers that will communicate must have the same DHCP proxy setting.

Configuring DHCP Proxy (GUI)

    Step 1   Choose Controller > Advanced > DHCP to open the DHCP Parameters page.
    Step 2   Select the Enable DHCP Proxy check box to enable DHCP proxy on a global basis. Otherwise, unselect the check box. The default value is selected.
    Step 3   Click Apply to commit your changes.
    Step 4   Click Save Configuration to save your changes.

    Configuring DHCP Proxy (CLI)

      Step 1   Enable or disable DHCP proxy by entering this command:

      config dhcp proxy {enable | disable}

      Step 2   View the DHCP proxy configuration by entering this command:

      show dhcp proxy

      Information similar to the following appears:

      
DHCP Proxy Behavior: enabled

      Configuring a DHCP Timeout (GUI)

        Step 1   Choose Controller > Advanced > DHCP to open the DHCP Parameters page.
        Step 2   Select the DHCP Timeout (5 - 120 seconds) check box to enable a DHCP timeout on a global basis. Otherwise, unselect the check box. The valid range is 5 through 120 seconds.
        Step 3   Click Apply to commit your changes.
        Step 4   Click Save Configuration to save your changes.

        Configuring a DHCP Timeout (CLI)

        Configure a DHCP timeout by entering this command:

        config dhcp timeout seconds