(Optional) Configuring Gateway Detection

Context

To enable a DHCP client to detect the status of the gateway, enable the gateway detection function. A DHCP client enabled with the gateway detection function sends an ARP Request packet to detect the gateway status after obtaining an IP address. If the DHCP client receives no ARP Reply packet within the detection period, it considers the gateway address incorrect or the gateway device faulty, and then re-applies for an IP address.

Procedure

Enter the system view.
```
system-view
```
Enter the interface view or sub-interface view.
```
interface interface-type interface-number [.subinterface-number ]
```
Only the S5720-EI, S5720-HI, S5730-HI, S5731-H, S5731S-H, S5731-S, S5731S-S, S6720-HI, S5732-H, S6730-H, S6730S-H, S6730-S, S6730S-S, S6720-EI, and S6720S-EI support sub-interfaces.
(Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.

By default, an Ethernet interface works in Layer 2 mode.

Only the S5720-EI, S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6730-H, S6730S-H, S6730-S, and S6730S-S support switching between Layer 2 and Layer 3 modes.
Configure the gateway detection function on the DHCP client.
```
dhcp client gateway-detect period period retransmit retransmit timeout time
```
By default, the gateway detection function is not configured on a DHCP client.