Service Manual

DHCP mode
pool name
2. Specify the client IP address.
DHCP <POOL>
host address
3. Specify the client hardware address.
DHCP <POOL>
hardware-address hardware-address type
• hardware-address: the client MAC address.
• type: the protocol of the hardware platform.
The default protocol is Ethernet.
Debugging the DHCP Server
To debug the DHCP server, use the following command.
• Display debug information for DHCP server.
EXEC Privilege mode
debug ip dhcp server [events | packets]
Using DHCP Clear Commands
To clear DHCP binding entries, address conicts, and server counters, use the following commands.
• Clear DHCP binding entries for the entire binding table.
EXEC Privilege mode.
clear ip dhcp binding
• Clear a DHCP binding entry for an individual IP address.
EXEC Privilege mode.
clear ip dhcp binding ip address
Congure the System to be a Relay Agent
DHCP clients and servers request and oer conguration 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 congure an interface on the Dell Networking system to relay the DHCP messages to a specic DHCP server using the ip
helper-address dhcp-address
command from INTERFACE mode, as shown in the following illustration. Specify multiple
DHCP servers by using the ip helper-address dhcp-address command multiple times.
When you congure the ip helper-address command, the system listens for DHCP broadcast messages on port 67. The
system rewrites packets received from the client and forwards them via unicast to the DHCP servers; 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 67 and the relay agent rewrites the destination address and forwards the packet to the client subnet via broadcast or
unicast, depending whether the client has set or cleared the BROADCAST ag in the DHCP Client PDUs.
NOTE: DHCP Relay is not available on Layer 2 interfaces and VLANs on the Z-Series and S4820T platforms. DHCP relay
agent is supported on Layer 2 interfaces and VLANs on the S3048–ON, S4810 and S4048–ON platforms.
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Dynamic Host Conguration Protocol (DHCP)