Describes router IOS restoration techniques

Many people may not know much about the router IOS restoration. So I have studied the solutions and restoration techniques for this problem. I will share them with you here, hoping to help you. In flash, the IOS file in the router is upgraded or restored after damage. In comparison, the second situation is more rare, but more serious, it often occurs in the router IOS recovery and upgrade operation errors or other hardware and software faults, resulting in the failure of the router system to work, resulting in the overall network paralysis.

At this time, we often need to repair the router in ROM Monitor mode. The following is an example of a student's problem. The student experienced the following faults when upgrading the IOS of a Cisco 2600 router:

System Bootstrap, Version 11.3 (2) XA4, release software (fc1)
Copyright (c) 1999 by Cisco Systems, Inc.
TAC: Home: SW: IOS: Specials for info
C2600 platform with 32768 Kbytes of main memory
Loadprog: bad file magic number: 0x0
Boot: cannot load "flash :"

Then, when the router Bootstrap program repeats the preceding process and fails, it enters the ROM Monitor mode. Rommon 1> boot: Run this command to reload the IOS file in flash. Boot: cannot determine first file name on device "flash:" After the router determines that the fault is caused by a failure to determine the IOS file in flash, we need to restore the IOS file from the TFTP Server to the flash of the router. In this case, we can do this in two ways: first, use a PC with the Cisco TFTP Server installed to recover the IOS router over Ethernet, and second, in ROM Monitor mode, xmodem is used to transmit files using the Console cable. Here, we give priority to the first method. The steps are as follows:

1. Connect a PC installed with Cisco TFTP Server to the Ethernet interface of the router through Ethernet to run the Cisco TFTP Server program.

2. Use a Super Terminal to log on to the Console of the vroconsole Console. The Console router is started and logged on when a fault is found. The terminal screen displays the following: rommon 2> set. This command displays the default vro settings.

PS1 = rommon! >
IP_ADDRESS = 192.168.1.1
IP_SUBNET_MASK = 255.255.255.0
DEFAULT_GATEWAY = 192.168.1.2
TFTP_SERVER = 192.168.1.2
TFTP_TIMEOUT = 20000
TFTP_RETRY_COUNT = 10
TFTP_FILE =/c2600-ik8o3s-mz.122-11.T/
? = 1

3. check the router settings and change the IP address of the PC to 192.168.1.2. We can also use the command TFTP_SERVER = 192.168.1.x to modify the settings, but ensure that the IP address of the router, the default gateway, and the IP address of the PC are in the same network segment ), this is simpler.