How to Backup Router Configuration to TFTP in GNS3

It may be a good idea to back up any settings you have made on the Cisco Router. If your router’s NVRAM fails, the initial configuration file cannot be loaded, and you will lose your existing settings.

Backing Up Cisco Router Configuration to TFTP Server

How to Backup Router Configuration on TFTP

There are many ways to back up the router configuration, one of which is to use a TFTP Server.

You can quickly copy the configuration and image files of all your network devices by placing a TFTP server in your existing network structure. However, since TFTP is an insecure transport protocol, you need to secure your server.

It is a good idea to back up your Cisco router’s startup-config and running-config files frequently.

Suppose a Cisco Router on your network fails. In that case, you can quickly add your backup device to the network environment and transfer the configuration file of the previous device to the new device via TFTP. This will ensure the continuity of your network.

Recovering configuration files is great. But what if the router’s operating system is completely erased? That’s when just the config file isn’t enough.

At this point, knowing the steps to back up the IOS image via TFTP is a lifesaver. Now, let’s take it a step further; you absolutely must practice this scenario on the GNS3. This way, you’ll gain the skill to restore the entire device software from scratch.

How to Save the Cisco Router’s Startup-Config and Running-Config Configuration Files

First, install the SolarWinds TFTP Server application on a VMware virtual machine, and then follow the steps below in order to configure the required settings.

Step 1

Create a new virtual machine with VMware, and then configure the VMnet settings, as shown in the image below.

Windows 10 VMnet Settings

Step 2

After creating VMnet3, change the IP address to 192.168.8.2.

VMnet3 IP Settings

Step 3

After completing the VMware Workstation settings, run GNS3 and create the topology, as shown in the image below.

A Cisco Router and Virtual Computer Connected to a Switch

Step 4

Once you have completed the VMware Workstation settings, run GNS3 and create the topology, as shown in the following illustration.

In addition, create a new user and configure the Console connection to connect to your Router from a remote computer.

First, you should set a username and a password for the console. That is the very first thing to do. But if you manage the router from far away, you need to make it even safer. To be honest, using SSH to connect to the router is much smarter than using older ways like Telnet.

line vty 0 4

Step 5

Ping the test from the VMware Windows 10 virtual machine to the Router’s FastEthernet0/0 interface.

ping 192.168.8.1

Step 6

Ping the Windows 10 machine from the router CLI console to test the network connection.

Ping 192.168.8.5

Step 7

After verifying the network connection, install and run the SolarWinds TFTP Server program on the Windows 10 VM. Then, start the service from the File menu.

Setting up a full Windows virtual machine to test a TFTP server can sometimes unnecessarily strain your system. You can create a lightweight computer using VPCS within GNS3 itself. With this small client, you can assign an IP address and ping directly.

SolarWinds TFTP Server

Step 8

Now, execute the following commands at the CLI command prompt to back up the running-config file on the router.

In the Remote Host section, do not forget to enter the IP address of the TFTP server!

In the following image, you can see that the router configuration has been successfully backed up!

R1#copy running-config tftp:
Address or name of remote host []? 192.168.8.5
Destination filename [r1-confg]? R1_Config
!!
974 bytes copied in 4.444 secs (219 bytes/sec)
R1#

copy running-config tftp:

Step 9

When you check the server, you can see that the router configuration file is saved as R1_Config.

You can also view the Log outputs on SolarWinds.

R1_Config

Step 10

You can check the existing configuration by opening the R1_Config file with Notepad.

Editing R1_Config

Step 11

After you have completed the backup process, first make a few changes to the existing settings to restore the router’s configuration file.

For example, configure the FastEthernet0/1 interface and save the settings with the save command.

Interface FastEthernet 0/1

Step 12

To restore the Router’s configuration, you must use the copy command again.

In Destination filename, press Enter to verify that the file name you want to restore is running-config.

R1#copy tftp: running-config
Address or name of remote host []? 192.168.8.5
Source filename []? R1_Config
Destination filename [running-config]?
Accessing tftp://192.168.8.5/R1_Config...
Loading R1_Config from 192.168.8.5 (via FastEthernet0/0): !
[OK - 974 bytes]

974 bytes copied in 0.772 secs (1262 bytes/sec)
R1#

R1#copy tftp: running-config

Step 13

Now, when you check the configuration with the show running-config command to verify the backup and restore operation, you can see that the backup file has been successfully restored.

Show running-config command

Show Commands

R1#show running-config
Building configuration...

Current configuration : 974 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R1
!
boot-start-marker
boot-end-marker
!
no aaa new-model
memory-size iomem 5
no ip icmp rate-limit unreachable
ip cef
!
no ip domain lookup
ip auth-proxy max-nodata-conns 3
ip admission max-nodata-conns 3
!
username cisco privilege 15 password 0 cisco123
!
ip tcp synwait-time 5
!
interface FastEthernet0/0
ip address 192.168.8.1 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
no ip address
shutdown
duplex auto
speed auto
!
ip forward-protocol nd
!
no ip http server
no ip http secure-server
!
no cdp log mismatch duplex
!
control-plane
!
gatekeeper
shutdown
!
line con 0
exec-timeout 0 0
privilege level 15
logging synchronous
line aux 0
exec-timeout 0 0
privilege level 15
logging synchronous
line vty 0 4
login local
!
end

R1#

How to Copy Cisco Router Settings ⇒ Video

You can watch the video below to save the settings of the Cisco Router and subscribe to our YouTube channel to support us!

Watch on YouTube

6 Critical Questions About Backing Up Cisco Routers in GNS3

Is NVRAM failure really that scary? What happens if I delay taking a backup?

The NVRAM is a small but the most critical corner of the router’s memory. If that tiny chip dies, the startup-config file vanishes. The result? When the device reboots, you face a blank factory setting. Entering the settings from scratch is a total waste of time.

Especially during a physical failure, the network can easily lock up. If you have a clean configuration file at hand, things change. You rack the new device and pull the configuration from TFTP in one minute.

I always tell users: do not think of backup only as a disaster scenario. Even when testing with GNS3 in a lab environment, you must keep a copy. You save yourself in seconds from situations where a wrong command makes you tear your hair out.

TFTP is so fast and easy. Why doesn’t everyone just use this protocol?

The secret lies in the fine line between simplicity and security. TFTP is a bare-naked protocol that works over UDP. It takes the file, drops it, and leaves. There is no encryption and no complex authentication mechanism.

In large corporate networks, this creates an unacceptable weakness. That is why you should never run TFTP on servers open to the outside world. But in an isolated lab network like here or on a management VLAN, its speed is unbeatable.

Frankly, it is a perfect fit for simulation environments like GNS3. Without struggling with complex SCP or FTP settings, you just type copy running-config tftp and move on. Just make sure you enter the IP address correctly.

What is the most common mistake when setting up the network between GNS3 and a VMware machine?

The most frustrating moment is when the ping does not go through. Usually, the culprit is the wrong VMnet adapter match. If you do not right-click the cloud icon in GNS3 and select the correct VMnet interface, the traffic hangs in the air.

The second big trap is IP addressing mismatch. You assign 192.168.8.1 to the router’s FastEthernet interface. Then you set 192.168.8.5 for the Windows machine in VMware. The logic looks correct, right?

But what if you set the subnet mask to 255.255.0.0? The network still works, but it is not good practice. Always try to stay on a /24 subnet. Also, check if the Windows firewall is off. UDP port 69 must be open for the TFTP connection.

I backed up the running-config, but I mix up the difference with startup-config. Which one is more important?

This confusion has happened to everyone who has suffered in network engineering. Running-config is your active settings working in RAM at that moment. Startup-config is the file sleeping in NVRAM that loads when the device boots.

Let’s say you gave an IP to the interface but did not do ‘write memory’. If the power goes out, that IP you set is lost. This is exactly why you should generally keep both in mind when backing up.

First, you save instant changes with copy run tftp. Then, you backup your chance to return to factory settings with copy start tftp. Remember, it makes more sense to restore onto the running-config. Because it writes directly to memory and you do not need to reset the device.

I am afraid the router will lock up when restoring the backup file. What should I watch out for?

This worry is completely valid. The slightest file corruption during the restore process can put the device in a weird state. Our first golden rule is this: use the command in the right direction. When you type copy tftp running-config, the current running settings are not deleted, they merge.

So, if you load an old backup, things can become a mess. To prevent this, it is a good idea to clean up with ‘erase startup-config’ before restoring and reboot the device. This way, the file from TFTP is written onto a clean canvas.

Secondly, be prepared for network disconnection. Interface IPs can change while the configuration file is loading. Do not be surprised if your Telnet or SSH connection suddenly drops. That is why I strongly suggest doing the restore while connected via a console cable.

Do you have a free and simple TFTP server recommendation other than SolarWinds?

SolarWinds really does the job, but it is famous for sometimes disappearing from the taskbar. As an alternative, I can only recommend Tftpd64. It is a tiny executable file that needs no installation. You open it, select the folder, done.

Another favorite of mine is Pumpkin. Its interface looks like it is from the MS-DOS era. But I would challenge anyone who criticizes its performance to a duel. It runs smoothly with zero resource consumption in a GNS3 environment.

Another tool you can choose with your eyes closed is Cisco’s own TFTP server. Yes, Cisco has its own software, and it is surprisingly simple. But do not forget: none of these tools are error-tolerant. If you mistype the file name, the router cries ‘file not found’. You must pay attention to uppercase and lowercase letters.

Conclusion

In this article, we have examined how to save config files for a Cisco router on the network. Thanks for following us!

How to Backup Cisco Router Configuration to TFTP Server