You can configure DHCP on an H3C access layer switch by enabling the DHCP service, creating IP address pools, assigning VLAN interfaces, and optionally configuring DHCP relay for clients on different subnets.

Enabling DHCP on the Switch

To start, enable the DHCP service on the H3C switch using the command:

dhcp enable

This activates the DHCP functionality on the device, allowing it to assign IP addresses to clients within configured VLANs .

Creating IP Address Pools

Define IP address pools for each subnet that the switch will serve. For example, to create a pool for VLAN 5:

dhcp server ip-pool VLAN5[Switch-dhcp-pool-VLAN5] network 192.168.5.0 255.255.255.0[Switch-dhcp-pool-VLAN5] gateway-list 192.168.5.1[Switch-dhcp-pool-VLAN5] excluded-ip-address 192.168.5.100

Repeat this process for other VLANs/subnets, specifying the network, gateway, and any IP addresses to exclude from dynamic allocation .

Assigning VLAN Interfaces

Each VLAN interface must have an IP address to act as the gateway for DHCP clients:

interface Vlan-interface5[Switch-Vlan-interface5] ip address 192.168.5.1 255.255.255.0[Switch-Vlan-interface5] dhcp select global

For VLANs where the switch acts as a relay, use:

[Switch-Vlan-interface6] dhcp select relay[Switch-Vlan-interface6] dhcp relay server-address 192.168.7.100

This ensures clients on different subnets can obtain IP addresses from a centralized DHCP server .

Configuring DHCP Relay (Optional)

If the DHCP server is on a different subnet, configure the switch as a relay agent:

interface Vlan-interfaceX[Switch-Vlan-interfaceX] dhcp select relay[Switch-Vlan-interfaceX] dhcp relay server-address <DHCP_Server_IP>

This forwards DHCP requests from clients to the server and returns the responses appropriately .

Verifying DHCP Operation

Check the DHCP bindings and active leases with:

display dhcp server ip-in-use display dhcp server statistics

These commands help confirm that clients are receiving IP addresses correctly and that the DHCP service is functioning as expected .

Best Practices

• Exclude static IP addresses (e.g., servers, printers) from dynamic pools to avoid conflicts.
• Ensure VLAN interfaces are up and reachable from clients.
• Use DHCP relay only when necessary to centralize DHCP services.
• Save the configuration after changes:

save

This ensures the DHCP configuration persists after a reboot . By following these steps, an H3C access layer switch can effectively provide DHCP services to clients within its VLANs or relay requests to a centralized DHCP server.