Restrictions For Dhcp-Based Autoconfiguration; Dhcp Autoconfiguration; Dhcp Auto-Image Update; Dhcp Server Configuration Guidelines - Cisco Catalyst 9200 Configuration Manual

Restrictions for DHCP-based Autoconfiguration

upgrade for all switches in the network helps ensure that each new device added to a network receives the
same image and configuration.
There are two types of DHCP image upgrades: DHCP autoconfiguration and DHCP auto-image update.
Restrictions for DHCP-based Autoconfiguration
• The DHCP-based autoconfiguration with a saved configuration process stops if there is not at least one
• Unless you configure a timeout, the DHCP-based autoconfiguration with a saved configuration feature
• The auto-install process stops if a configuration file cannot be downloaded or if the configuration file is
• The configuration file that is downloaded from TFTP is merged with the existing configuration in the

DHCP Autoconfiguration

DHCP autoconfiguration downloads a configuration file to one or more devices in your network from a DHCP
server. The downloaded configuration file becomes the running configuration of the device. It does not over
write the bootup configuration saved in the flash, until you reload the device.

DHCP Auto-Image Update

You can use DHCP auto-image upgrade with DHCP autoconfiguration to download both a configuration and
a new image to one or more devices in your network. The device (or devices) downloading the new
configuration and the new image can be blank (or only have a default factory configuration loaded).
If the new configuration is downloaded to a switch that already has a configuration, the downloaded
configuration is appended to the configuration file stored on the switch. (Any existing configuration is not
overwritten by the downloaded one.)
To enable a DHCP auto-image update on the device, the TFTP server where the image and configuration files
are located must be configured with the correct option 67 (the configuration filename), option 66 (the DHCP
server hostname) option 150 (the TFTP server address), and option 125 (description of the Cisco IOS image
file) settings.
After you install the device in your network, the auto-image update feature starts. The downloaded configuration
file is saved in the running configuration of the device, and the new image is downloaded and installed on the
device. When you reboot the device, the configuration is stored in the saved configuration on the device.

DHCP Server Configuration Guidelines

Follow these guidelines if you are configuring a device as a DHCP server:
• You should configure the DHCP server with reserved leases that are bound to each device by the device
System Management Configuration Guide, Cisco IOS XE Gibraltar 16.10.x (Catalyst 9200 Switches)
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Layer 3 interface in an up state without an assigned IP address in the network.
tries indefinitely to download an IP address.
corrupted.
running configuration but is not saved in the NVRAM unless you enter the write memory or
copy running-configuration startup-configuration privileged EXEC command. If the downloaded
configuration is saved to the startup configuration, the feature is not triggered during subsequent system
restarts.
hardware address.
Performing Device Setup Configuration