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DEMO: Changing the Boot Loading File

Keeping Cisco IOS devices up to date is essential for maintaining security and expanding feature support. This content covers the full process of upgrading IOS firmware on a Cisco router using a TFTP server.

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About this video

Cisco IOS upgrades are a routine but high-stakes maintenance responsibility for network administrators. Security advisories regularly identify vulnerabilities in older IOS versions, and feature requirements such as IPv6 routing may demand a more capable image than what is currently installed. Before beginning the upgrade, it is important to assess the available flash storage and confirm whether the device can hold both the old and new images simultaneously or whether the existing image must be deleted first to make room. The upgrade workflow on a Cisco router typically begins by removing the existing IOS image from flash using the delete command with recursive and force options, then transferring the new image from a TFTP server using the copy tftp flash command. Once the transfer completes, the directory is verified to confirm the file is present and intact. The boot system command in global configuration mode is then used to direct the router to load the new image on next reload, and the running configuration is saved before restarting the device. After the router reloads, the show version command confirms whether the upgrade was successful by displaying the active IOS version. A correct result shows the newly installed image, verifying that the device is now running updated, patched software with any newly required feature sets enabled. Careful attention to each step in this process is essential, as skipping or misordering operations can result in a device that fails to boot and requires console-based recovery.

What you'll learn

What's covered

Updating Cisco IOS

Aligned to

Cisco CCNA
4.9 Describe the capabilities and functions of TFTP/FTP in the network
Cisco CCST Cybersecurity
3.4 Implement software and hardware updates

Key terms

Trivial File Transfer Protocol
TFTP
A simplified file transfer protocol that uses UDP and provides no authentication, directory browsing, or error recovery, making it fast and lightweight. TFTP is commonly used to transfer configuration files, IOS images, and boot files to and from network devices in controlled environments.
Flash Memory
A type of non-volatile solid-state memory that stores data on chips and retains information without power; it is the storage technology behind SSDs, USB drives, and SD cards.
Internetworking Operating System
IOS
Cisco's proprietary operating system running on most Cisco routers and switches, providing a command-line interface for device configuration, management, and monitoring. IOS is the foundation for Cisco's network equipment and has evolved into variants such as IOS XE, IOS XR, and NX-OS.
Boot System Command
A Cisco IOS global configuration command that specifies which IOS image file the router should load during startup.
Router
A network device that forwards data packets between networks based on IP addresses.

Topics

Cisco Ios Router Configuration Tftp Firmware Upgrade Boot Loader Networking

Transcript

As things go along there's updates that come out to your Cisco IOS device, and you should be updating it, because there are security concerns that come up with this equipment. Every once in a while you should update your equipment so it has the latest and greatest updates on your machine and is keeping it safe. So that's what we're going to go through, is that process of updating the Cisco IOS on these devices.

Checking What Is on the Flash

The first thing that I'm going to do is take a look at what's on there right now, so I'm going to take a look at the flash. I can just type in dir to take a look at the directory, and we see that the directory has a c1841, because that's the style of router.

I'm actually going to be updating it to something that can handle IPv6 on this router, because this one is not capable of handling IPv6.

Making Room for the New Image

The first thing that I know of is that there is about 35 megs that are available on this machine — about 35 megs available — and the file that I have that's going to be transferring over is more than that. So I can't have two of these files on here at the same time; I have to delete one and then switch over. Which can be problematic: if I don't switch over correctly, then it can be problematic when it comes time to booting this up, and it can be a real headache. So I want to make sure that I go through this process correctly.

The first thing that I need to do is remove this file right here, and the way I do that is delete. This is actually a directory, so I need to delete the directory and anything underneath it, so I'll type in recursive, and we'll also use the force, and then we are going to take this file out of the flash. I will just copy this because I want to make sure I get the exact name here, so I'll copy that and hit enter, and then that's going to delete the file. I can check it just by doing directory: no files in this directory.

Copying the New Image from TFTP

The next step here is, I've already set up a TFTP server that I'm going to download that to this device now. So I need to use the copy command, because I'm copying, and I'm copying from the TFTP server, so I'll do tftp and then the address of that server, which is 10.1.0.3. So there's the address, and then the file that exists on the server, which is c advanced enterprise k9-mz-1.m5.bin. So that's the one that I'm going to be copying over right there.

I'll hit enter, and — oh, I do need to say where it's copying to, and it's copying to the flash drive, so I'll type in flash here. It asks me for a destination file name, and it just copies what the file name exists on the TFTP server, and that's fine, I'm just going to accept the default. So I'm going to hit enter there, and then it's going to go through the process of loading it. These exclamation points are showing me that this is loading, so I'm going to give this a couple of minutes to go through the process of taking this file down from the TFTP server and storing it on flash.

Once the file is copied over I just want to confirm it, so I'm going to type in directory once again, and I see that this is in fact the new copy of the file, so we are good to go there.

Setting the Boot System File

Now what I need to do is set this machine to actually access that. I need to be in the global configuration mode to do that, so I'm going to go into the global configuration mode, and then the command I'm going to use is boot system, and then the file that we're going to access. It's in flash, and then it's this file right here — easiest for me to just highlight it and copy it over — and then I'll hit enter.

I'm going to exit out of here, and I'm going to save this, so copy run start. And then we'll see if it boots up correctly.

Once your router has reloaded, all we need to do is a show version just to see if it took. When I see here, the software that it's using is in fact the updated software, and so we are good to go.

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