Dhcp-Based Autoconfiguration And Image Update; Restrictions For Dhcp-Based Autoconfiguration; Dhcp Autoconfiguration; Dhcp Auto-Image Update - Cisco Catalyst 9400 System Management Configuration Manual

Performing Device Setup Configuration
has had a chance to formally request the address. If the device accepts replies from a BOOTP server and
configures itself, the device broadcasts, instead of unicasts, TFTP requests to obtain the device configuration
file.
The DHCP hostname option allows a group of devices to obtain hostnames and a standard configuration from
the central management DHCP server. A client (device) includes in its DCHPDISCOVER message an option
12 field used to request a hostname and other configuration parameters from the DHCP server. The configuration
files on all clients are identical except for their DHCP-obtained hostnames.

DHCP-Based Autoconfiguration and Image Update

You can use the DHCP image upgrade features to configure a DHCP server to download both a new image
and a new configuration file to one or more devices in a network. Simultaneous image and configuration
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 devices (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
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.
System Management Configuration Guide, Cisco IOS XE Bengaluru 17.4.x (Catalyst 9400 Switches)
DHCP-Based Autoconfiguration and Image Update
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