Router disaster recovery steps.

Reference: http://www.cisco.com/en/US/docs/routers/access/1800/1841/software/configuration/guide/b_rommon.html#wp1064046

Before you load any new ios to replace the new one, remember to backup everything from the router’s flash to your tftp server!

I only backed up my IOS but did not backup the softwares in the router, after the disaster recovery everything except the IOS was gone!

It’s a painful experience! Luckily it is not my company’s router, it is MY router…lol…

Here’s the step:

Step 1:

rommon 3 > IP_ADDRESS=172.30.10.1

Set your router’s ip address.

Step 2:

rommon 4 > IP_SUBNET_MASK=255.255.255.0

Set your router’s subnet mask.

Step 3:

rommon 5 > DEFAULT_GATEWAY=172.30.10.1

Set the default gateway.

Step4:
rommon 6 > TFTP_SERVER=172.30.10.2

Set your TFTP server source address.

Step 5:
rommon 7 > TFTP_FILE=c1841-ipbase-mz.150-1.M3.bin

Set the path of your file which you want to download from the tftp server.

Step 6:

rommon 8 > FE_PORT=0

Set your fastethernet port, I was using fa0/0, so I choose 0.

IMPORTANT: Rommon tftp download command only works with fixed routed ports, those ports came with the network module are not supported.

Step 7:
rommon 9 > set
PS1=rommon ! >
WARM_REBOOT=FALSE
RELOAD_TYPE=1
BSI=0
RANDOM_NUM=851113558
RET_2_RTS=14:03:50 UTC Tue Oct 19 2010
RET_2_RCALTS=1287497034
?=0
IP_ADDRESS=172.30.10.1
IP_SUBNET_MASK=255.255.255.0
DEFAULT_GATEWAY=172.30.10.1
TFTP_SERVER=172.30.10.2
TFTP_FILE=c1841-ipbase-mz.150-1.M3.bin
FE_PORT=0
rommon 10 >

This step is to verify your settings before you do the download.

Step 8:

rommon 10 > tftpdnld

IP_ADDRESS: 172.30.10.1
IP_SUBNET_MASK: 255.255.255.0
DEFAULT_GATEWAY: 172.30.10.1
TFTP_SERVER: 172.30.10.2
TFTP_FILE: c1841-ipbase-mz.150-1.M3.bin
TFTP_MACADDR: e8:04:62:dc:5d:c4
TFTP_VERBOSE: Progress
TFTP_RETRY_COUNT: 18
TFTP_TIMEOUT: 7200
TFTP_CHECKSUM: Yes
FE_PORT: 0
FE_SPEED_MODE: Auto Detect

Invoke this command for disaster recovery only.
WARNING: all existing data in all partitions on flash: will be lost!
Do you wish to continue? y/n:  [n]:  y

This is the ultimate command that will download my IOS to my flash and at the same time erased everything in my flash!

The above is the screenshot taken as a memento. File was transferring at a very slow speed…60KB/s -_-”

Here’s the output from ROMMON after the IOS was loaded, the default is after downloaded checksum will be validated, if your IOS is corrupted or checksum is incorrect you will expect your router to reboot persistently:

File reception completed.
Validating checksum.
Copying file c1841-ipbase-mz.150-1.M3.bin to flash:.
program load complete, entry point: 0x8000f000, size: 0xcb80

Format: Drive communication & 1st Sector Write OK…
Writing Monlib sectors.
………………………………………………………………………………………….
Monlib write complete

Format: All system sectors written. OK…
Format: Operation completed successfully.

Format of flash: complete
program load complete, entry point: 0x8000f000, size: 0xcb80

1841-1#sh flash:
-#- –length– —–date/time—— path
1     28605944 Oct 26 1906 00:15:44 c1841-ipbase-mz.150-1.M3.bin

35405824 bytes available (28606464 bytes used)

Only the IOS exists 😦

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