Self-defined option configuration example

Network requirements

As shown in Figure 31, the DHCP client (Switch B) obtains an IP address and PXE server addresses from the DHCP server (Switch A). The IP address belongs to subnet 10.1.1.0/24. The PXE server addresses are 1.2.3.4 and 2.2.2.2.

The DHCP server assigns PXE server addresses to DHCP clients through Option 43, a self-defined option. The format of Option 43 and that of the PXE server address sub-option are shown in Figure 19 and Figure 21, respectively. The value of Option 43 configured on the DHCP server in this example is 80 0B 00 00 02 01 02 03 04 02 02 02 02. The number 80 is the value of the sub-option type. The number 0B is the value of the sub-option length. The numbers 00 00 are the value of the PXE server type. The number 02 indicates the number of servers. The numbers 01 02 03 04 02 02 02 02 indicate that the PXE server addresses are 1.2.3.4 and 2.2.2.2.

Figure 31: Network diagram

Configuration procedure

  1. Specify IP addresses for the interfaces. (Details not shown.)

  2. Configure the DHCP server:

    # Enable DHCP.

    <SwitchA> system-view
    [SwitchA] dhcp enable
    

    # Enable the DHCP server on VLAN-interface 2.

    [SwitchA] interface vlan-interface 2
    [SwitchA-Vlan-interface2] dhcp select server global-pool
    [SwitchA-Vlan-interface2] quit
    

    # Configure DHCP address pool 0.

    [SwitchA] dhcp server ip-pool 0
    [SwitchA-dhcp-pool-0] network 10.1.1.0 mask 255.255.255.0
    [SwitchA-dhcp-pool-0] option 43 hex 80 0B 00 00 02 01 02 03 04 02 02 02 02
    

Verifying the configuration

After the preceding configuration is complete, Switch B can obtain its IP address on 10.1.1.0/24 and PXE server addresses from the Switch A. You can use the display dhcp server ip-in-use command on the DHCP server to view the IP addresses assigned to the clients.