Dhcp Clear Commands; Configure The System To Be A Relay Agent - Dell Force10 C150 Configuration Manual

DHCP Clear Commands

Task
Clear DHCP binding entries for the entire binding
table.
Clear a DHCP binding entry for an individual IP
address.
Clear a DHCP address conflict.
Clear DHCP server counters.

Configure the System to be a Relay Agent

DHCP clients and servers request and offer configuration information via broadcast DHCP messages.
Routers do not forward broadcasts, so if there are no DHCP servers on the subnet, the client does not
receive a response to its request and therefore cannot access the network.
You can configure an interface on the Dell Force10 system to relay the DHCP messages to a specific
DHCP server using the command
Figure 13-4. Specify multiple DHCP servers by entering the
multiple times.
ip helper-address
When
system rewrites packets received from the client and forwards it via unicast; the system rewrites the
destination IP address and writes its own address as the relay device. Responses from the server are unicast
back to the relay agent on port 68, and the relay agent rewrites the destination address and forwards the
packet to the client subnet via broadcast.
Note: DHCP Relay is not available on Layer 2 interfaces.
Note: In a Private VLAN, ip helper-address is configured from Interface VLAN mode of the Primary
VLAN. When ip helper-address is configured, the system listens for DHCP broadcast messages on port
67. The system rewrites packets received from the clients on primary and secondary (community and
isolated) VLANs and forwards it via unicast; the system rewrites the destination IP address and writes
primary VLANs IP as the relay device. Responses from the server are unicast back to the relay agent on
port 68, and the relay agent rewrites the destination address and forwards the packet to the client subnet
via broadcast.
320 | Dynamic Host Configuration Protocol
Command Syntax
clear ip dhcp binding
clear ip dhcp binding ip address
clear ip dhcp conflict
clear ip dhcp server statistics
ip helper-address dhcp-address
is configured, the system listens for DHCP broadcast messages on port 67. The
from INTERFACE mode, as shown in
ip helper-address dhcp-address
Command Mode
EXEC Privilege
EXEC Privilege
EXEC Privilege
EXEC Privilege
command