Dhcp Client Operation With Other Features - Dell S4048T Configuration Manual

• Management routes added by the DHCP client are not added to the running configuration.
NOTE: Management routes added by the DHCP client include the specific routes to reach a DHCP server
in a different subnet and the management route.

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 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.
• An entry in the DHCP snooping table is not added for a DHCP client interface.
DHCP Server
A switch can operate as a DHCP client and a DHCP server. DHCP client interfaces cannot acquire a dynamic
IP address from the DHCP server running on the switch. Acquire a dynamic IP address from another DHCP
server.
Dynamic Host Configuration Protocol (DHCP) 356