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Chapter 3 41
Configuration
Setting Configuration Values
How Configuration Values are Used
The E2050 LAN/GPIB Gateway uses the default configuration values and/or
the configuration values that you changed or set depending on certain
situations, such as when the power is cycled on the Gateway or when the
Config Preset button on the back panel of the Gateway is pressed.
This section summarizes how configuration values are used in various
situations. This information can help you better maintain the Gateway and
more easily troubleshoot problems you may encounter with the Gateway.
This section also describes how the Gateway uses the configuration values
during the Gateway’s power-on initialization sequence (after power is cycled
on the Gateway) and when the Gateway’s
Config Preset button is pressed.
During the Power-on
Initialization
Sequence
When power is applied to the Gateway and the hardware self-test has
completed, the networking subsystem is initialized. What happens during
this initialization sequence depends on what configuration method, if any,
has been used to configure the Gateway.
After Telnet
Configuration
If you have used the Telnet configuration method to set the IP address, the
Gateway will not send BOOTP requests at power-on to configure itself.
Instead, the Gateway will simply use the IP address and any other
configuration values that were set through Telnet.
Prior to Successful
Configuration with
BOOTP or BOOTP
with TFTP
If you are applying power to the Gateway before it has been successfully
configured with an actual IP address via BOOTP or BOOTP with TFTP, the
Gateway will send BOOTP requests to the BOOTP server for up to five
minutes. When the BOOTP server’s bootpd daemon receives the request,
it will search the /etc/bootptab configuration file for an entry that
matches the Gateway’s LAN hardware address.
When a match is found, bootpd retrieves the configuration data associated
with the entry and sends it to the Gateway as a BOOTP response. The
Gateway then completes its initialization using the configuration data
provided in the BOOTP response.
After BOOTP or
BOOTP with TFTP
Configuration
If you have applied power to the Gateway one or more times since
configuration, the Gateway will have successfully completed BOOTP
requests in the past. Thus, the Gateway will send BOOTP requests for only
one minute before it stops and then uses the previous BOOTP response
stored in the Gateway’s non-volatile memory.