H3C Technologies H3C SecBlade NetStream Cards - Manual (Page 223)

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• If all the above operations fail, the device requests the default configuration file from the TFTP server.
TFTP request sending mode
The device selects to unicast or broadcast a TFTP request by using the following flow:
• If a legitimate TFTP server IP address is contained in the DHCP response, the device unicasts a TFTP
request to the TFTP server.
• If not, the device resolves the TFTP server domain name contained in the DHCP response to the
corresponding IP address through the DNS server. If successful, the device unicasts a TFTP request
to the TFTP server; if not, the device broadcasts a TFTP request.
• If the IP address and the domain name of the TFTP server are not contained in the DHCP response
or they are illegitimate, the device broadcasts a TFTP request.
NOTE:
•
After broadcasting a TFTP request, the device selects the TFTP server that responds first to obtain the
configuration file. If the requested configuration file does not exist on the TFTP server, the request
operation fails, and the device removes the temporary configuration and starts up with factory defaults.
• If the device and the TFTP server reside in different subnets, you need to configure the UDP Helper
function for the gateway to change the broadcast TFTP request from the device to a unicast packet and
forward the unicast packet to the specified TFTP server.
Executing the configuration file
After obtaining the configuration file, the device removes the temporary configuration and executes the
configuration file. If no configuration file is obtained, the device removes the temporary configuration
and starts up with factory defaults.
NOTE:
The configuration file is deleted after executed, so save the configuration by using the save command.
Otherwise, the device has to perform automatic configuration again after reboot. For more information
about the save command, see the chapter “Configuration file management commands.”