• Supported Platforms
• MX Series

• Related Topics
• Group-Specific DHCP Relay Options
• Deleting DHCP Local Server and DHCP Relay Override Settings

Overriding the Default DHCP Relay Configuration Settings

Subscriber management enables you to override certain default DHCP relay agent configuration settings. You can override the settings at the global level, for a named group of interfaces, or for a specific interface within a named group.

• To override global default DHCP relay agent configuration options, include the overrides statement and its subordinate statements at the [edit forwarding-options dhcp-relay] hierarchy level.
• To override DHCP relay configuration options for a named group of interfaces, include the statements at the [edit forwarding-options dhcp-relay group group-name] hierarchy level.
• To override DHCP relay configuration options for a specific interface within a named group of interfaces, include the statements at the [edit forwarding-options dhcp-relay group group-name interface] hierarchy level.

To override default DHCP relay agent configuration settings:

1. Specify that you want to configure override options.

   Global override:

   [edit forwarding-options dhcp-relay]user@host# edit overrides

   Group level override:

   [edit forwarding-options dhcp-relay]user@host# edit group boston overrides

   Per-interface override:

   [edit forwarding-options dhcp-relay]user@host# edit group boston overrides interface fe-1/0/1.2
2. (Optional) Enable DHCP relay proxy mode.

   See Enabling DHCP Relay Proxy Mode.

3. (Optional) Overwrite the giaddr in DHCP packets the DHCP relay agent forwards.

   See Overwriting giaddr Information.

4. (Optional) Replace the IP source address in DHCP relay request and release packets with the gateway IP address (giaddr).

   See Replacing the DHCP Relay Request and Release Packet Source Address.

5. (Optional) Override the DHCP relay agent information option (option 82) in DHCP packets.

   See Overriding Option 82 Information.

6. (Optional) Override the setting of the broadcast bit in DHCP request packets and use the Layer 2 unicast transmission method.

   See Using Layer 2 Unicast Transmission for DHCP Packets.

7. (Optional) Trust DHCP client packets that have a giaddr of 0 and that contain option 82 information.

   See Trusting Option 82 Information.

8. (Optional) Override ARP table population in distrusted environments.

   See Disabling ARP Table Population.

9. (Optional) Override the maximum number of DHCP clients allowed per interface.

   See Specifying the Maximum Number of DHCP Clients Per Interface.

10. (Optional) Configure client auto logout.

    See DHCP Auto Logout Overview.

11. Enable or disable support for DHCP snooped clients on interfaces.

    See Allowing DHCP Snooped Clients on Interfaces.

12. (Optional) Send release messages to the DHCP server when clients are deleted.

    See Sending Release Messages When Clients Are Deleted.

13. (Optional) Disable DHCP relay agent on specific interfaces.

    See Disabling DHCP Relay.