How To Back Up and Restore Configuration on CISCO Devices

Sooner or later in your networking career, you will realize that there is nothing more important than backing up your system’s configuration. Days, or even months of hard work can disappear in a matter of seconds. That’s why it is so important to always take the measures to prevent this from happening.

Performing backups often is importnat but also testing them can be invaluable because you need to make sure that you can rely on them when needed.

So let’s start by learning how to connect to a Cisco router by using telnet and console access. Then we will see how to perform configuration backup to a TFTP server and how to restore the backup in case it is needed.

 

Connecting to a Cisco Router Using Console

Step 1: Attach a console cable to the console port (Rj-45) located at the back of the router.

Step 2: Open a new HyperTerminal instance from Start-All Programs-Accessories-Communications-HyperTerminal, enter a random name to this connection and choose the com port to use for connecting to the router. Adjust the following port settings to the com port:

Bits per second: 9600
Data bits: 8
Parity: none
Stop bits: 1
Flow control: Hardware

Step 3: After pressing [Enter] a few times you will see the Router> prompt. Go to menu view-font of the hyperterminal and select courier font with font size 14.

Write enable to enter into privileged mode (after issuing the correct enable secret). Here are the steps:

[Router name]>
[Router name]>enable
Password: ……….
[Router name]#

Connecting to a Cisco Router Using Telnet

Note that in order to be able to telnet onto a router, a telnet password must have been configured on the router and also telnet access should not be disabled on the specific router.

Before installing a new router you must provide a password for the telnet access on the router, otherwise you will not be able to telnet to it.

Use the console to connect to the router:

[Router name] enable
Password: ……….[insert enable secret here]
[Router name]# sh run

Press [enter] until you see a sentence like: line vty 0 4 (see the example below). Below this sentence you should see a password. If not then you should provide a password. If a password is set but no exec line is seen like in the example below, then telnet is blocked and you should unblock it.

Example:

Line vty 0 4
Password surpass
No exec

a. To Provide a telnet Password

Router#config t
Router(Config)#line vty 0 4
Router(Config)#login
Router(Config)#password [password name]
Press [Ctrl][z] and issue sh run to ensure that password has been set

b. To Unblock telnet Access on Router

Router#config t
Router(Config)#line vty 0 4
Router(Config)#exec
C:>telnet 10.176.100.2
Password: ……….
[Router name]>enable
Password: ……….
[Router name]#

Backing Up Router Configuration

To copy the configuration from the router to the TFTP server you can use the copy run tftp command. It will backup the router configuration thats stored in DRAM. Then you will be asked to enter the address of the TFTP server and the name of the destination file on TFTP server like this:

[Router name] #copy run tftp — to copy the running configuration to TFTP server

Address or name of remote host []? 172.16.10.2 — the ip address of TFTP server

Destination filename [routername-confg]? /Backup/Router01.cfg — the folder path on the server where the configuration file will be stored)

 

Restoring Router Configuration

In this section I’ll show you how to restore a running router with basic configuration and also how to restore a new router with no basic configuration — both of which scenarios you’ll probably run into.

 

1. Restoring a Running Router with Basic Configuration

In case the router has the basic configuration (i.e. router ports are assigned to subnet), use the command copy TFTP run and then complete the rest of the requirements like this:

[router name]# show run — to see the running configuration

[router name]#copy tftp run — to copy the configuration file from TFTP server to the running configuration of the router

Address or name of remote host []?172.16.10.2 — TFTP server address

Source filename[]?/Backup/Router01.cfg — the configuration file to be copied to the router

[router name]#show run

[router name]#show interfaces

[router name]#copy run start

We issue show run command to verify that the configuration has been copied to the router. Use show interfaces command to ensure that the interfaces where we have cables connected to them are up. Issue the command copy run start to copy the configuration from running configuration (DRAM) to Startup configuration (NVRAM).

The following is an example of what you will see on the screen when you issue the show interfaces command:

Vlan1 is up, line protocol is up
.
.
.
fastethernet 0/1 is up, line protocol is up
.
.
.
fastethernet 0/2 is down, line protocol is down
.
.
.

Usually fastethernet ports are brought up on their own as soon as the ethernet cable is attached to them. In case a certain port is still down after we have connect a cable in it we use:

[Router name]#config t
[Router name](config)#int fastethernet0/[router port]
[Router name](config-if)#no shutdown

2. Restoring a New Router with No Basic Configuration

a. Provide basic router configuration

In case we install a new router with no configuration, then we have to incorporate this router into the subnet before restoring the final configuration. We have to assign an IP address and subnet mask to interface Vlan1.

First we have to go through the old configuration files either from the old router or from the tfrp server and look for the IP address and subnet that the router was configured with, on its previous location. This information will look like this:

interface vlan1
ip address [ip address] [subnet]

Make a note of both IP address and subnet and then log onto your new router with the console cable using a hyperterminal. Issue passwords and then issue the following:

[Router name]#config t
[Router name](Config)#int vlan1
[Router name](Config-if)#ip address [ip address] [subnet]
[Router name](Config-if)#no shutdown
Press [CTRL][Z]
[Router name]# show run — to see that IP address on vlan1 has been set

b. Copy configuration from TFTP server to the router

[Router name] #copy TFTP run
Address or name of remote host []?172.16.10.2
Source filename[]?/Backup/Router01.cfg
[router name]#show run
[router name]#show interfaces
[router name]#copy run start

My Advice: Save This Article in a Safe Place

This article has all the details of backing up and restoring configuration files on Cisco switches/routers. Whatever you do — don’t underestimate this information.

Believe me when I say, this should be your first and most important thing you need to learn and apply in practice if you want to sleep peacefully at night.

My Advice:

  • Always do backups at frequent intervals.
  • Always save them in safe and secure places.
  • Always test them to see that they will operate as expected in case of real need.

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