Cisco Router IOS Backup Configuration

Today I’m gonna discuss about some Cisco device administration guide such as IOS backup and Restore. An IOS (Internetwork Operating System) powers routers to be communicating each other. Cisco IOS is un-debated market leader for producing IOS. Backing up of IOS image is important to fix corrupted Cisco IOS. Restoring of IOS image from backup is also crucial in your networking career. There are many possible ways to backup Cisco IOS viz FTP, TFTP or RCP. This article focused on TFTP method to backup IOS.

SolarWinds provides free TFTP Server.

Cisco Device Administration Guides

1. IOS Backup and Restore (TFTP)
2. IOS Upgrade Process (TFTP)
3. Running Configuration Backup (TFTP)

TFTP (Trivial File Transfer Protocol)

We have used TFTP to backup Cisco IOS.

• TFTP works on UDP port 69; it doesn’t require any authentication (user name and password) and designed for LAN usage.
• Can only read and write files from TFTP server. It cannot list, delete or rename files or directories.
• TFTP intended for firmware images and configuration file transfer to network appliances like router, switch, IP phone, firewall etc.

Download SolarWinds TFTP Server Free

Working Environment

Install and configure SolarWinds TFTP Server. (For learning purpose you can use Cisco PacketTracer, but GNS3 is not compatible as the IOS is already in the hard disk of our PC. Show flash command doesn’t supported by GNS3.)

• Router Console Port = Connected to Laptop
• Router FastEthernet0/0 = 192.168.2.1/24
• TFTP Server = 192.168.2.2/24

Configure IP address in router interface f0/0; let me get in to the Cisco IOS backup process.

Cisco Router IOS Backup Configuration Guide

First you have to do is to identify the IOS image file from Flash. For that run show flash command. It will list the files in flash memory of Cisco router.

Router#show flash:

System flash directory:
File Length Name/status
3 33591768 c1841-advipservicesk9-mz.124-15.T1.bin
2 28282 sigdef-category.xml
1 227537 sigdef-default.xml
[33847587 bytes used, 30168797 available, 64016384 total]
63488K bytes of processor board System flash (Read/Write)

My router is running IOS c1841-advipservicesk9-mz.124-15.T1.bin version. So I’m going to transfer this image to TFTP Server.

Router#copy flash tftp:
Source filename []? c1841-advipservicesk9-mz.124-15.T1.bin
Address or name of remote host []? 192.168.2.2
Destination filename [c1841-advipservicesk9-mz.124-15.T1.bin]?

Writing c1841-advipservicesk9-mz.124-15.T1.bin...!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
[OK - 33591768 bytes]

33591768 bytes copied in 0.554 secs (6366420 bytes/sec)

Commands Explanation

Cisco Router IOS Restore Factory Default rommon

If something went wrong your IOS image may be corrupt. Such cases we can restore the router with previously backed up IOS.
For lab environment lets delete the current IOS in the router, to do so run the command Router#delete:[IOS File Name]

Router#delete c1841-advipservicesk9-mz.124-15.T1.bin
Delete filename [c1841-advipservicesk9-mz.124-15.T1.bin]?
Delete flash:/c1841-advipservicesk9-mz.124-15.T1.bin? [confirm]

Now no more IOS in our router, reboot router by entering

Router#reload
Proceed with reload? [confirm]
System Bootstrap, Version 12.3(8r)T8, RELEASE SOFTWARE (fc1)
Initializing memory for ECC
..
c2811 processor with 524288 Kbytes of main memory
Main memory is configured to 64 bit mode with ECC enabled

Readonly ROMMON initialized

Boot process failed...

The system is unable to boot automatically. The BOOT
environment variable needs to be set to a bootable
image.
rommon 1 >

A corrupted router will prompt rommon 1 > always. We are going to assign a temporary IP address to the router.

rommon 1 > IP_ADDRESS=192.168.2.1
rommon 2 > IP_SUBNET_MASK=255.255.255.0
rommon 3 > DEFAULT_GATEWAY=192.168.2.2
rommon 4 > TFTP_SERVER=192.168.2.2
rommon 5 > TFTP_FILE=c1841-advipservicesk9-mz.124-15.T1.bin
rommon 6 > TFTP_CHACKSUM=0
rommon 7 > tftpdnld

IP_ADDRESS: 192.168.2.1
IP_SUBNET_MASK: 255.255.255.0
DEFAULT_GATEWAY: 192.168.2.2
TFTP_SERVER: 192.168.2.2
TFTP_FILE: c1841-advipservicesk9-mz.124-15.T1.bin
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

The file downloaded successfully. Now reboot by entering

rommon 10 > reset

Now the router will boot up normally.

Self decompressing the image :
########################################################################## [OK]
Restricted Rights Legend

Use, duplication, or disclosure by the Government is
subject to restrictions as set forth in subparagraph
(c) of the Commercial Computer Software - Restricted
Rights clause at FAR sec. 52.227-19 and subparagraph
(c) (1) (ii) of the Rights in Technical Data and Computer
Software clause at DFARS sec. 252.227-7013.

cisco Systems, Inc.
170 West Tasman Drive
San Jose, California 95134-1706

Commands Explanation

Troubleshooting of Restore Process

• Make sure TFTP Server is running and the IOS image exist in the server’s root folder.
• Commands are case sensitive and must follow the way I followed in above steps.
• TFTP Server should be connected to router via first inbuilt interface of router.
• Use cross cable if you connected TFTP server and router directly.
• Use straight through cable if you connected TFTP server and router over a switch.

Lab Environment using Cisco Packet Tracer

Here I wanna show you couple of things that you could take care if you practice IOS backup in Cisco Packet Tracer.

• Server having inbuilt TFTP Service, make sure it is running
• Verify the file names in TFTP Server

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