Load IOS via TFTP in ROMMON Mode
Without an IOS, the nonworking router will boot up in ROMmon mode. The prompt
will look like this:
rommon>
How to Download a Software Image to a Cisco 2600 through TFTP Using the
tftpdnld ROMmon Command (http://www.cisco.com/warp/public/471/76.html):
Here are the settings you must set for the tftpdnld command to work:
rommon> set
IP_ADDRESS=10.253.100.126
IP_SUBNET_MASK=255.255.0.0
TFTP_SERVER=10.253.15.72
DEFAULT_GATEWAY=10.253.1.1
TFTP_FILE={the name of the IOS that is saved on the PC}
However, your settings may not contain any of the required variables for the
tftpdnld command. By default, it may look something like this:
rommon 9 > set
PS1=rommon ! >
BSI=0
RET_2_RUTC=0
RET_2_RTS=
?=1
To set the IP address of the broken router, you would use the following:
IP_ADDRESS=10.253.100.126
After setting your values, run the tftpdnld command, which will replace the IOS.
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How do I load the IOS by X-Modem
This is for an 800 but it should be pretty close for any X-modem upload.
Step 1 Increase the router console port baud rate:
router# set baud = 115200
Step 2 Reset the console port:
router# reset
Step 3 Optional. If you want the router console port to continue to run
at 115,200 baud after you reboot, you can save the configuration:
router# save
Step 4 Change your host baud rate to 115,200.
For the new baud rate to take effect, you might need to save the new
baud rate, exit from the terminal emulator, and establish a new session.
Step 5 Download the software image from the host:
router# upload xmodem
The following is an example of output displayed while the software is
downloading:
Ready for X/Modem upload ...
[note: no status bar for xmodem transfers,
abort with Control-X or break]
upload: succeeded (312 seconds).
Step 6 From your host, enter the Xmodem send command for your terminal
emulation software. For example, if you are using HyperTerm, select
Transfer > Send File. The Send File dialog box appears. Click Browse
to locate the software image. Select XMODEM as the protocol, and
click Send.
Step 7 Delete the old software image:
router# delete filename
You must have enough free Flash memory to store the new image. You may
need to delete more than one old software image to free up enough Flash
memory. To see the names of existing files in Flash memory, use the list
command.
Step 8 Save the new software image to Flash memory:
router# save file = filename
where filename is the name of the new software image that was
transferred to the router.
Step 9 Boot the new software image:
router# boot
Step 10 Optional. If you do not want the router console port to continue
to run at 115,200 baud after you reboot, change your terminal
emulation software to run at 9600 baud.
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How can I retrieve an IOS configuration using SNMP.
It is valuable to have backup copies of your Cisco equipment configurations.
Configurations often change over time and tracking these changes is often
overlooked. How about automatically storing your network configurations? The
quick and simple answer is, SNMP.
Using the MIB .1.3.6.1.4.1.9.2.1.55 you can write the config to a tftp server on
your network.
For example, to write the configuration of a Cisco router or switch to a tftp
server from an AIX host the command would be of form...
snmpset -c .1.3.6.1.4.1.9.2.1.55. octetstring