DHCP user class configuration example

As shown in Figure 22, the DHCP relay agent (Router A) forwards DHCP packets between DHCP clients and the DHCP server (Router B). Enable Router A to handle Option 82 so that it can add Option 82 in DHCP requests and then convey them to the DHCP server.

Configure the address allocation scheme as follows:

Router B assigns the DNS server address 10.10.1.20/24 and the gateway address 10.10.1.254/24 to clients on subnet 10.10.1.0/24.

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

2. Configure DHCP:

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

   <RouterB> system-view
   [RouterB] dhcp enable
   [RouterB] dhcp server relay information enable
   

   # Enable the DHCP server on the interface GigabitEthernet1/0/1.

   [RouterB] interface gigabitethernet 1/0/1
   [RouterB-GigabitEthernet1/0/1] dhcp select server
   [RouterB-GigabitEthernet1/0/1] quit
   

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

   [RouterB] dhcp class tt
   [RouterB-dhcp-class-tt] if-match rule 1 option 82
   [RouterB-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.

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

   # Create DHCP address pool aa.

   [RouterB] dhcp server ip-pool aa
   

   # Specify the subnet for dynamic allocation.

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

   # Specify the address range for dynamic allocation.

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

   # Specify the address range for the user class tt.

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

   # Specify the address range for the user class ss.

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

   # Specify the gateway and the DNS server.

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

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

# On the DHCP server, display the IP addresses assigned to the clients.

[RouterB] 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)