Using Dhcp Clear Commands; Configure The System To Be A Relay Agent - Dell Z9500 Configuration Manual

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Using DHCP Clear Commands

To clear DHCP binding entries, address conflicts, 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

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 Networking system to relay the DHCP messages to a specific 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 configure 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 flag in the DHCP Client PDUs.

Dynamic Host Configuration Protocol (DHCP)