Configuring The Dhcp Relay Agent To Send A Dhcp-Release Request; Configuring The Dhcp Relay Agent Security Functions - H3C S9500 Series Operation Manual

Operation Manual – DHCP
H3C S9500 Series Routing Switches
Note:
You can specify at most twenty DHCP server groups on S9500 series routing
switches.
Up to eight DHCP server addresses can be configured for each DHCP server group.
The IP addresses of DHCP servers that belong to the DHCP server group and those
of relay agent's interfaces cannot be on the same subnet. Otherwise, the client
cannot obtain an IP address.
A DHCP server group can correlate with one or multiple DHCP relay agent
interfaces, while a relay agent interface can only correlate with one DHCP server
group. Using the dhcp relay server-select command repeatedly overwrites the
previous configuration. However, if the specified DHCP server group does not exist,
the interface still uses the previous correlation.
The group-id in the dhcp relay server-select command was specified by the dhcp
relay server-group command.

3.2.5 Configuring the DHCP Relay Agent to Send a DHCP-Release Request

Sometimes, you need to release a client's IP address manually on the DHCP relay
agent. With this task completed, the DHCP relay agent can actively send a
DHCP-RELEASE request that contains the client's IP address to be released. Upon
receiving the DHCP-RELEASE request, the DHCP server then releases the IP address
for the client.
With this feature enabled in system view, the DHCP-RELEASE request will be sent to
those DHCP servers correlated with the DHCP relay agent interfaces.
To configure the DHCP relay agent in system view to send a DHCP-RELEASE request,
use the following commands:
Enter system view
Configure the DHCP relay agent in
system view to send a
DHCP-RELEASE request

3.2.6 Configuring the DHCP Relay Agent Security Functions

I. Create static bindings and enable invalid IP address check
The DHCP relay agent dynamically records clients' IP-to-MAC bindings to generate a
dynamic binding after clients got IP addresses. It also supports static binding, which
To do...
3-5
Chapter 3 DHCP Relay Agent Configuration
Use the command...
system-view
dhcp relay release ip
client-ip
Remarks
—
Required