Users Guide

• The switch can obtain a dynamically assigned IP address from a DHCP server. A start-up conguration is not received. Use bare metal
provisioning (BMP) to receive conguration parameters (Dell Networking OS version and a conguration le). 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
Conguring 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 congured by default as a DHCP client to acquire a dynamic IP
address from a DHCP server.
• By default, the switch is congured to operate in BMP mode as a DHCP client that sends DHCP requests to a DHCP server to retrieve
conguration information (IP address, boot-image lename, and conguration le). All ports and management interfaces are brought up
in Layer 3 mode and pre-congured with no shutdown and no ip address. For this reason, you cannot enter conguration
commands to set up the switch. To interrupt a BMP process, prevent a loop from occurring, and apply the Dell Networking OS image
and startup conguration stored in the local ash, enter the stop bmp command from the console. To recongure the switch so that
it boots up in normal mode using the Dell Networking OS image and startup conguration le in local ash, enter the reload-type
normal-reload
command and save it to the startup conguration:
Dell# reload-type normal-reload
Dell# write memory
Dell# reload
• To re-enable BMP mode for the next reload, enter the reload-type jump-start command.
DHCP Client Operation with Other Features
The DHCP client operates with other Dell Networking OS features, as the following describes.
Stacking
The DHCP client daemon runs only on the master unit and handles all DHCP packet transactions. It periodically synchronizes the lease le
with the standby unit.
When a stack failover occurs, the new master requires the same DHCP server-assigned IP address on DHCP client interfaces. The new
master reinitiates a DHCP packet transaction by sending a DHCP discovery packet on nonbound interfaces.
Virtual Link Trunking (VLT)
A DHCP client is not supported on VLT interfaces.
VLAN and Port Channels
DHCP client conguration and behavior are the same on Virtual LAN (VLAN) and port-channel (LAG) interfaces as on a physical interface.
DHCP Snooping
A DHCP client can run on a switch simultaneously with the DHCP snooping feature as follows:
• If you enable DHCP snooping globally on a switch and you enable a DHCP client on an interface, the trust port, source MAC address,
and snooping table validations are not performed on the interface by DHCP snooping for packets destined to the DHCP client daemon.
The following criteria determine packets destined for the DHCP client:
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Dynamic Host Conguration Protocol (DHCP)