Using Dhcp Clear Commands; Configure The System To Be A Relay Agent - Dell S4048–ON 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

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.

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.

Dynamic Host Configuration Protocol (DHCP)