DHCP Snooping with Option-82

When DHCP Dynamic Host Configuration Protocol snooping with Option-82 is enabled on the switch, following behavior is expected:

1.

The host generates a DHCP request and broadcasts it on the network.

2.

When the switch receives DHCP request, it adds option-82 information in the packet.

3.

If the IP address of the relay agent is configured, the switch adds the IP address in the DHCP packet.

4.

The switch forwards the DHCP request that includes the option-82 field to the DHCP server.

5.

The DHCP server receives the packet. If the server is option-82 capable, it can use the information in the option-82 fields to assign IP addresses and implement policies, such as restricting the number of IP addresses that can be assigned to a single remote ID or circuit ID. The DHCP server then echoes the option-82 field in the DHCP reply.

6.

The DHCP server unicasts the reply to the switch if the request was relayed to the server by the switch. When the client and server are on the same subnet, the server broadcasts the reply. The switch verifies that it originally inserted the option-82 data by inspecting the remote id and circuit id fields. The switch removes the option-82 field and forwards the packet to the switch port that connects to DHCP client A DHCP client is a hardware device or software that uses DHCP to get the network configuration information from a DHCP Server.     VRF: VRF creates a logically isolated routing table within a single physical network device. Each VRF instance works as an independent routing instance that enables separate network traffic, maintains different routing tables, and provides network isolation. that sent the DHCP request.