Reference Guide

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 (FTOS 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 only on Ethernet interfaces: 10Gigabit, 40 Gigabit, and
100/1000/10000 Ethernet Interfaces. The DHCP client is supported on 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.
DHCP Client Operation with Other Features
The DHCP client operates with other FTOS 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 file 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 configuration 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:
– DHCP is enabled on the interface.
– The user data protocol (UDP) destination port in the packet is 68.
– The chaddr (change address) in the DHCP header of the packet is the same as the interface’s MAC
address.
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