Users Guide

DHCP and USB Auto-Configuration 595
A file is not automatically deleted after it is downloaded. The file does not
take effect upon a reboot unless you explicitly save the configuration (the
saved configuration takes effect upon reboot). If you do not save the
configuration downloaded by the Auto Configuration feature, the Auto
Configuration process occurs again on a subsequent reboot or when the
DHCP lease expires. This may result in one of the previously downloaded files
being overwritten.
What Are the Dependencies for DHCP Auto Configuration?
The Auto Configuration process from TFTP servers depends upon the
following network services:
• A DHCP server must be configured on the network with appropriate
services.
• An image file and a text file containing the image file name for the switch
must be available from a TFTP server if a firmware update is desired.
• A configuration file (a default file such as host.cfg or a specific path/file
name using DHCP option 67 boot-file-name) for the switch must be
available from a TFTP server if a configuration update is desired from a
specific file on the TFTP server. DHCP option 67 may contain a path
name in addition to the file name.
• The switch must be connected to the network and have a Layer-3 interface
that is in an UP state.
• A DNS server must contain an IP address to hostname mapping for the
TFTP server if the DHCP server response identifies the TFTP server by
name.
• A DNS server must contain an IP address to hostname mapping for the
switch if a < hostname>.cfg file is to be downloaded.
• If a default gateway is needed to forward TFTP requests, an IP helper
address for TFTP needs to be configured on the default gateway.