C
HAPTER
2
| Initial Switch Configuration
Basic Configuration
– 73 –
DOWNLOADING A
CONFIGURATION FILE
REFERENCED BY A
DHCP SERVER
Information passed on to the switch from a DHCP server may also include a
configuration file to be downloaded and the TFTP servers where that file
can be accessed. If the Factory Default Configuration file is used to
provision the switch at startup, in addition to requesting IP configuration
settings from the DHCP server, it will also ask for the name of a bootup
configuration file and TFTP servers where that file is stored.
If the switch receives information that allows it to download the remote
bootup file, it will save this file to a local buffer, and then restart the
provision process.
Note the following DHCP client behavior:
◆ The bootup configuration file received from a TFTP server is stored on
the switch with the original file name. If this file name already exists in
the switch, the file is overwritten.
◆ If the name of the bootup configuration file is the same as the Factory
Default Configuration file, the download procedure will be terminated,
and the switch will not send any further DHCP client requests.
◆ If the switch fails to download the bootup configuration file based on
information passed by the DHCP server, it will not send any further
DHCP client requests.
◆ If the switch does not receive a DHCP response prior to completing the
bootup process, it will continue to send a DHCP client request once a
minute. These requests will only be terminated if the switch’s address is
manually configured, but will resume if the address mode is set back to
DHCP.
To successfully transmit a bootup configuration file to the switch the DHCP
daemon (using a Linux based system for this example) must be configured
with the following information:
◆ Options 60, 66 and 67 statements can be added to the daemon’s
configuration file.
◆ By default, DHCP option 66/67 parameters are not carried in a DHCP
server reply. To ask for a DHCP reply with option 66/67 information, the
DHCP client request sent by this switch includes a “parameter request
list” asking for this information. Besides, the client request also
includes a “vendor class identifier” that allows the DHCP server to
identify the device, and select the appropriate configuration file for
download. This information is included in Option 55 and 124.
Table 3: Options 60, 66 and 67 Statements
Option
Statement
Keyword Parameter
60 vendor-class-identifier a string indicating the vendor class identifier
66 tftp-server-name a string indicating the tftp server name
67 bootfile-name a string indicating the bootfile name
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