Enabling Duplicated Address Detection; Displaying And Maintaining The Dhcp Client; Dhcp Client Configuration Example; Network Requirements - HP 5920 Series Configuration Manual

Step
1. Enter system view.
2. Enter interface view.
3. Configure a DHCP client ID
for the interface.

Enabling duplicated address detection

DHCP client detects IP address conflict through ARP packets. An attacker can act as the IP address owner
to send an ARP reply, making the client unable to use the IP address assigned by the server. HP
recommends you to disable duplicate address detection when ARP attacks exist on the network.
To enable duplicated address detection:
Step
1. Enter system view.
2. Enable duplicate address
detection.

Displaying and maintaining the DHCP client

Execute display command in any view.
Task
Display DHCP client information.

DHCP client configuration example

Network requirements

As shown in
an IP address, DNS server address, and static route information. The DHCP client IP address resides on
network 10.1.1.0/24. The DNS server address is 20.1.1.1. The next hop of the static route to network
20.1.1.0/24 is 10.1.1.2.
The DHCP server uses Option 121 to assign static route information to DHCP clients.
Option 121 format. The destination descriptor field contains two parts: subnet mask length and
destination network address. In this example, the value of the destination descriptor field is 18 14 01 01.
It is a hexadecimal number indicating that the subnet mask length is 24 and destination network address
Figure 24, on a LAN, Switch B contacts the DHCP server through VLAN-interface 2 to obtain
Command
system-view
interface interface-type
interface-number
dhcp client identifier { ascii string |
hex string | mac interface-type
interface-number }
Command
system-view
dhcp client dad enable
Command
display dhcp client [ verbose ] [ interface interface-type
interface-number ]
58
Remarks
N/A
N/A
By default, an interface generates
the DHCP client ID based on its
MAC address. If the interface has
no MAC address, it uses the MAC
address of the first Ethernet
interface to generate its client ID.
Remarks
N/A
By default, the duplicate address
detection feature is enabled on an
interface.
Figure 23 shows the