Cisco Cisco SG200-26P 26-port Gigabit PoE Smart Switch メンテナンスマニュアル
Administration
File Management
Cisco Small Business SF200E Series Advanced Smart Switch
70
3
DHCP Auto Configuration
The switch supports Auto Configuration through DHCP to facilitate configuration
deployment and upgrades. This feature enables the configuration of a switch
automatically when no configuration file is found in device storage during the boot
process or when a newer configuration file is available for download.
deployment and upgrades. This feature enables the configuration of a switch
automatically when no configuration file is found in device storage during the boot
process or when a newer configuration file is available for download.
NOTE
The Auto Configuration feature depends upon the proper configuration of other
devices in the network, including a DHCP or BOOTP server, a TFTP server, and if
necessary, a DNS server.
devices in the network, including a DHCP or BOOTP server, a TFTP server, and if
necessary, a DNS server.
Overview
During startup, the switch attempts communication with a DCHP server to obtain
its IP address and other information. If Auto Configuration is enabled, the switch
may also download a startup configuration file, depending on the TFTP server and
startup configuration file name it receives from the DHCP server. Auto
Configuration is enabled by default.
its IP address and other information. If Auto Configuration is enabled, the switch
may also download a startup configuration file, depending on the TFTP server and
startup configuration file name it receives from the DHCP server. Auto
Configuration is enabled by default.
DHCP Auto Configuration initiates when the switch is rebooted with Auto
Configuration enabled, and any of the following conditions occur:
Configuration enabled, and any of the following conditions occur:
1. Information on the TFTP server and Startup Configuration is received from the
DHCP server, and Auto Configuration has not previously downloaded the
configuration file.
configuration file.
2. Information on the TFTP server and Startup Configuration is received from the
DHCP server, and the configuration file name differs from the file name
advertised in a previous DHCP message.
advertised in a previous DHCP message.
3. The Startup Configuration file is not present and no information on the TFTP
server or Startup Configuration is received from the DHCP server.
When conditions 1 and 2 occur, the switch saves the file to flash memory. Upon
subsequent startups, it compares the stored file name to the name specified in
option 66/67 in the current DHCP message. If they differ, the new file is
downloaded and written to flash memory.
subsequent startups, it compares the stored file name to the name specified in
option 66/67 in the current DHCP message. If they differ, the new file is
downloaded and written to flash memory.
NOTE
When the system boots up for the first time, the switch does not have a specific
name for the configuration file received from the DHCP server, as it has not
downloaded a Startup Configuration file yet. If these options are received in the
DHCP message, then that file name is saved and the download process begins.
name for the configuration file received from the DHCP server, as it has not
downloaded a Startup Configuration file yet. If these options are received in the
DHCP message, then that file name is saved and the download process begins.
When option 3 occurs, the switch looks for the TFTP server and Startup
Configuration file as described in
Configuration file as described in