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Most switches have a TFTP client,
allowing you to retrieve and send configuration files from/to a TFTP
server. The actual syntax to perform TFTP configuration file transfers
varies based on the type of switch and version of Supervisor module
installed in the switch.
To save a configuration file from
either a Supervisor I or Supervisor II module, use the write
net command. Figure
shows a session writing a configuration file to a TFTP server. The
server IP address and the filename are clearly seen in the output.
For the switch to obtain
the new configuration over the network, after having cleared the
configuration, you need to restore a valid IP address and default
gateway setting. Retrieving a file from the server uses the command configure
network. When retrieving a
file, you need to specify the source filename on the TFTP server. 
For complete system recovery, make
sure that you have a copy of the configuration file of each switch
stored somewhere other than on the switch itself. If anything
happens to the Supervisor module, you might not be able to recover
the configuration file. It is a big mistake to have to rebuild the
entire configuration file from scratch during a system outage,
especially when a backup copy could have easily been created as a
backup on a network-accessible machine.
Through TFTP, you can store your
configuration file on a TFTP server and recover it later when
needed. The syntax varies, depending upon the version of Supervisor
module you have. This section assumes you have either a Cisco IOS
command-based switch or a set command-based switch with a Supervisor
module.
As a side note, TFTP servers are
inherently weak security wise. It is highly recommended that you do
not keep your configuration files in a TFTP directory space until
you actually need to retrieve them. Anyone who compromises your TFTP
server can modify the configuration files without your knowledge. The prudent network
administrator will maintain configuration files in a secure
directory space and copy them back to the TFTP directory space only
when he or she is ready to use them. Although this adds another step
to the recovery process, the security benefits definitely outweigh
the procedural disadvantages.
Transferring Cisco IOS command-based
switch configuration files via TFTP to another device works the same
as with a router. The command copy
running-config tftp will copy
the configuration file to a TFTP server at the location you specify.
The recovery process works in reverse. To recover a configuration
file from a TFTP server, issue the command copy
tftp running-config. This
will load the configuration file you specify into NVRAM and the
"active" memory of the switch.
Transferring Supervisor III and
Catalyst 4000/6000 configuration files via TFTP to another device
looks much like it does with a router. The command copy
config flash | file-id | tftp
copies the configuration file to one of three locations. You can
store the configuration file in the bootflash memory, a Flash card
in a Flash slot (with a supervisor module that supports flash
cards), or to a
TFTP server. When copying configuration files to or from the switch,
you need to specify the source filename. Because of the Flash
architecture on the Supervisor III, you might have several
configuration files stored locally. However, only one can be active.
Therefore, you need to specify which of the local files you are
trying to copy.
Recovering a configuration file works
in reverse. If you intend to retrieve the file from a TFTP server,
use the command copy tftp flash | file-id |
config.
When retrieving, you can write the configuration file to your
bootflash, a Flash card, or to the running configuration. If you
intend to write the configuration file to your running
configuration, use the command form copy
tftp config. Figure
shows a session recovering the configuration filename cat to a Flash
device.
If you store your configuration file
in your Flash, you can recover it with the command copy
flash tftp | file-id | config.
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Lab
Activity |
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In
this lab activity, you will learn how to copy
your current configuration from a Catalyst 4000
switch to a TFTP server. |
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Lab
Activity |
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In
this lab activity, you will learn how to copy
your current configuration from a Catalyst 2900
switch to a TFTP server. |
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