Example: Configuring DHCP user class

As shown in Figure 19, the DHCP relay agent (Switch A) forwards DHCP packets between DHCP clients and the DHCP server (Switch B). Enable switch A to support Option 82 so that switch A can add Option 82 in the DHCP requests sent by the DHCP clients.

Configure the address allocation scheme as follows:

For clients on subnet 10.10.1.0/24, the DNS server address is 10.10.1.20/24 and the gateway address is 10.10.1.254/24.

1. Specify IP addresses for interfaces on the DHCP server and the DHCP relay agent. (Details not shown.)

2. Configure DHCP services:

   # Create DHCP user class tt and configure a match rule to match client requests with Option 82.

   <SwitchB> system-view
   [SwitchB] dhcp class tt
   [SwitchB-dhcp-class-tt] if-match rule 1 option 82
   [SwitchB-dhcp-class-tt] quit
   

   # Create DHCP user class ss and configure a match rule to match DHCP requests in which the hardware address is six bytes long and begins with aabb-aabb-aab.

   [SwitchB] dhcp class ss
   [SwitchB-dhcp-class-ss] if-match rule 1 hardware-address aabb-aabb-aab0 mask ffff-ffff-fff0
   [SwitchB-dhcp-class-ss] quit
   

   # Create DHCP address pool aa.

   [SwitchB] dhcp server ip-pool aa
   

   # Specify the subnet for dynamic allocation.

   [SwitchB-dhcp-pool-aa] network 10.10.1.0 mask 255.255.255.0
   

   # Specify the address range for dynamic allocation.

   [SwitchB-dhcp-pool-aa] address range 10.10.1.2 10.10.1.100
   

   # Specify the address range for user class tt.

   [SwitchB-dhcp-pool-aa] class tt range 10.10.1.2 10.10.1.10
   

   # Specify the address range for user class ss.

   [SwitchB-dhcp-pool-aa] class ss range 10.10.1.11 10.10.1.26
   

   # Specify the gateway address and the DNS server address.

   [SwitchB-dhcp-pool-aa] gateway-list 10.10.1.254
   [SwitchB-dhcp-pool-aa] dns-list 10.10.1.20
   [SwitchB-dhcp-pool-aa] quit
   

   # Enable DHCP and configure the DHCP server to handle Option 82.

   [SwitchB] dhcp enable
   [SwitchB] dhcp server relay information enable
   

   # Enable DHCP server on VLAN-interface10.

   [SwitchB] interface vlan-interface 10
   [SwitchB-Vlan-interface10] dhcp select server
   [SwitchB-Vlan-interface10] quit
   

# Verify that clients matching the user classes can obtain IP addresses in the specified ranges and all other configuration parameters from the DHCP server. (Details not shown.)

# Display the IP address assigned by the DHCP server.

[SwitchB] display dhcp server ip-in-use
IP address       Client identifier/    Lease expiration      Type
                 Hardware address
10.10.1.2        0031-3865-392e-6262-  Jan 14 22:25:03 2015  Auto(C)
                 3363-2e30-3230-352d-
                 4745-302f-30
10.10.1.11       aabb-aabb-aab1        Jan 14 22:25:03 2015  Auto(C)