Dell C1048P Port Extender Networking Configuration Guide for the C9000 Series - Page 335
Debugging the DHCP Server, Using DHCP Clear Commands, Con the System to be a Relay Agent
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host address 3 Specify the client hardware address. DHCP 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 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 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 Networking system to relay the DHCP messages to a specific DHCP server using the ip helper-address command from INTERFACE mode, as shown in the following illustration. Specify multiple DHCP servers by using the ip helper-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) 335
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