H3C S7500E Series Ethernet Switches Operation Manual

Operation Manual – DHCP
H3C S7500E Series Ethernet Switches Chapter 3 DHCP Relay Agent Configuration
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III. Enabling unauthorized DHCP servers detection
There are unauthorized DHCP servers on networks, which reply DHCP clients with
wrong IP addresses.
With this feature enabled, upon receiving a DHCP message with the siaddr field (IP
address of the server assigning IP addresses to clients) not being 0 from a client, the
DHCP relay agent will record the value of the siaddr field and the information on the
interface receiving the DHCP message. The administrator can use this information to
check out any DHCP unauthorized servers.
Follow these steps to enable unauthorized DHCP server detection:
To do… Use the command… Remarks
Enter system view
system-view
—
Enable unauthorized
DHCP server detection
dhcp relay
server-detect
Required
Disabled by default.
 Note:
With the unauthorized DHCP server detection enabled, the device puts a record once
for each DHCP server. The administrator needs to find unauthorized DHCP servers
from the log information. After the recorded information of a DHCP server is cleared, a
new record will be put for the DHCP server.
3.3.6 Configuring the DHCP Relay Agent to Support Option 82
I. Prerequisites
You need to complete the following tasks before configuring the DHCP relay agent to
support Option 82.
z Enabling DHCP
z Enabling the DHCP relay agent on the specified interface
z Correlating a DHCP server group with relay agent interfaces
II. Configuring the DHCP relay agent to support Option 82
Follow these steps to configure the DHCP relay agent to support Option 82:
To do… Use the command… Remarks
Enter system view
system-view
—
Enter interface view
interface interface-type
interface-number
—