Administrator Guide

To view the ip helper-address configuration for an interface, use the show ip interface command from EXEC privilege mode.
Example of the show ip interface Command
R1_E600#show ip int gigabitethernet 1/3
GigabitEthernet 1/3 is up, line protocol is down
Internet address is 10.11.0.1/24
Broadcast address is 10.11.0.255
Address determined by user input
IP MTU is 1500 bytes
Helper address is 192.168.0.1
192.168.0.2
Directed broadcast forwarding is disabled
Proxy ARP is enabled
Split Horizon is enabled
Poison Reverse is disabled
ICMP redirects are not sent
ICMP unreachables are not sent
Configure the System to be a DHCP Client
A DHCP client is a network device that requests an IP address and configuration parameters from a DHCP server.
Implement the DHCP client functionality as follows:
• The switch can obtain a dynamically assigned IP address from a DHCP server. A start-up configuration is not received. Use bare metal
provisioning (BMP) to receive configuration parameters (Dell EMC Networking OS version and a configuration file). BMP is enabled as
a factory-default setting on a switch.
A switch cannot operate with BMP and as a DHCP client simultaneously. To disable BMP in EXEC mode, use the stop bmp
command. After BMP stops, the switch acts as a DHCP client.
• Acquire a dynamic IP address from a DHCP client is for a limited period or until the client releases the address.
• A DHCP server manages and assigns IP addresses to clients from an address pool stored on the server. For more information, refer to
Configuring the Server for Automatic Address Allocation.
• Dynamically assigned IP addresses are supported on Ethernet, VLAN, and port-channel interfaces.
• The public out-of-band management interface and default VLAN 1 are configured by default as a DHCP client to acquire a dynamic IP
address from a DHCP server.
• By default, the switch is configured to operate in BMP mode as a DHCP client that sends DHCP requests to a DHCP server to
retrieve configuration information (IP address, boot-image filename, and configuration file). All ports and management interfaces are
brought up in Layer 3 mode and pre-configured with no shutdown and no ip address. For this reason, you cannot enter
configuration commands to set up the switch. To interrupt a BMP process, prevent a loop from occurring, and apply the Dell EMC
Networking OS image and startup configuration stored in the local flash, enter the stop bmp command from the console. To
reconfigure the switch so that it boots up in normal mode using the Dell EMC Networking OS image and startup configuration file in
local flash, enter the reload-type normal-reload command and save it to the startup configuration:
DellEMC# reload-type normal-reload
DellEMC# write memory
DellEMC# reload
• To re-enable BMP mode for the next reload, enter the reload-type jump-start command.
• If the management port is associated with any non-default VRF, then the ip address dhcp command does not work.
Configuring the DHCP Client System
This section describes how to configure and view an interface as a DHCP client to receive an IP address.
Dell EMC Networking OS Behavior: The ip address dhcp command enables DHCP server-assigned dynamic addresses on an
interface. The setting persists after a switch reboot. To stop DHCP transactions and save the dynamically acquired IP address, use the
shutdown command on the interface. To display the dynamic IP address and show DHCP as the mode of IP address assignment, use the
show interface type slot/port command. To unconfigure the IP address, use the no shutdown command when the lease
timer for the dynamic IP address is expired. The interface acquires a new dynamic IP address from the DHCP server.
To configure a secondary (backup) IP address on an interface, use the ip address command at the INTERFACE configuration level.
Use the no ip address dhcp command to:
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Dynamic Host Configuration Protocol (DHCP)