Users Guide

DHCP and USB Auto-Configuration 591
After the switch successfully downloads and installs the new image, it
automatically reboots. On reboot, Auto Configuration will run again if no
saved configuration is present on the switch and no USB configuration is
present.
The download or installation might fail for one of the following reasons:
• The path or filename of the image on the TFTP server does not match the
information specified in the file identified in DHCP option 125 sub option
5.
• The downloaded image is the same as the current image.
• The validation checks, such as valid CRC Checksum, fails.
If the download or installation was unsuccessful, a message is logged.
Obtaining Configuration Files
If the DHCP OFFER identifies a host-specific configuration path/file, in
DHCP option 67, the switch attempts to download and process the host
configuration file. The DHCP option 67 field may contain both a relative
path and file name component in the form directory/subdirectory/.../filename
up to 128 characters in length.
Host configuration files consist of a series of CLI configuration commands,
one per line. The host configuration file is processed in Privileged Exec mode.
Only commands that will appear in the running-config are processed. Action
commands such as locate will cause an error and the remainder of the
configuration script will not be processed.
The TFTP client makes three unicast requests if the TFTP server is
reachable. A TFTP server is not reachable if it does not respond to ARP, if its
DNS name (DHCP option 66) does not resolve, or if the TFTP server does
NOTE: In stack of switches, the downloaded image is pushed to all members
attached to the stack at the time of download. For members who join the stack
after the download, the Stack Firmware Synchronization feature, if enabled, will
push the downloaded image to all members.
NOTE: The configuration file is required to have a file name that matches the
following pattern: "*.cfg"