Configuring A Dhcp Relay Address Pool - HP FlexNetwork MSR2003 Configuration Manual

Configuring a DHCP relay address pool

This feature allows DHCP clients of the same type to obtain IP addresses and other configuration
parameters from the DHCP servers specified in the matching relay address pool.
It applies to scenarios where the DHCP relay agent connects to clients of the same access type but
classified into different types by their locations. In this case, the relay interface typically has no IP
address configured. You can use the gateway-list command to specify the gateway address for
clients matching the same relay address pool and bind the gateway address to the device's MAC
address.
Upon receiving a DHCP DISCOVER or REQUEST from a client that matches a relay address pool,
the relay agent processes the packet as follows:
•
Fills the giaddr field of the packet with the specified gateway address.
•
Forwards the packet to all DHCP servers in the matching relay address pool.
The DHCP servers select an address pool according to the gateway address.
If PPPoE users are in the network, follow these restrictions and guidelines when you configure the
relay address pool:
•
Enable the DHCP relay agent to record DHCP relay entries by using the dhcp relay
client-information record command. When a PPPoE user goes offline, the DHCP relay agent
can find a matching relay entry and send a DHCP-RELEASE message to the DHCP server.
This mechanism ensures the DHCP server to be aware of the releasing of the IP address in a
timely manner.
•
The remote-server command also configures the device as a DHCP relay agent. You do not
need to enable the DHCP relay agent by using the dhcp select relay command.
To configure a DHCP relay address pool:
Step
1. Enter system view.
2. Create a DHCP relay
address pool and enter its
view.
3. Specify gateway addresses
for the clients matching the
relay address pool.
4. Specify DHCP servers for
the relay address pool.
Command
system-view
dhcp server ip-pool pool-name
gateway-list ip-address&<1-8>
[ export-route ]
remote-server
ip-address&<1-8>
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Remarks
N/A
By default, no DHCP relay address
pool exists.
This command is the same for
creating DHCP address pools on a
DHCP server. However, the relay
address pool names are not
necessarily the same as the server
address pool names.
By default, no gateway address is
specified.
You can specify a maximum of eight
gateway addresses, but only the first
one takes effect.
By default, no DHCP server is
specified for the relay address pool.
You can specify a maximum of eight
DHCP servers for one relay address
pool for high availability. The relay
agent forwards DHCP DISCOVER
and REQUEST packets to all DHCP
servers in the relay address pool.