Network Basics: TFTP Installation and Use - dummies

Network Basics: TFTP Installation and Use

By Edward Tetz

Network administrators must sometimes update the Internetwork Operating System (IOS) file, or firmware of a Cisco device. Using a TFTP server is the most common way of getting a the file to your network device.

Cisco used to provide a free TFTP server that you could download to load the image via the server, but Cisco has discontinued this because there are many inexpensive or free alternatives. The following are a couple good (and free!) choices to use as your TFTP server:

  • Tftpd32: Open source TFTP server software. (Tftpd32)

  • The SolarWinds TFTP Server: SolarWinds’ TFTP server is available for download from its FTP site. When running their server software, SolarWinds is a bit chatty about telling you about great products for purchase, but submitting to their advertising is the price you pay for their “free” software. (Solarwinds)

Both of these user interfaces are shown in the following figure:


With most TFTP servers, you

  1. Specify a directory to share or serve up via TFTP with the main screen showing you server activity.

    You get a list of the IP addresses and what files they have uploaded or downloaded from the directory.

  2. Download your IOS image files from Cisco.

    You need a support agreement to be able to download the IOS image files for your device. You can find this software at the Cisco Support portal, following the Download Software link on that page, and then following the navigation tool on the page to locate the IOS image for your Cisco device. After you have them, you can move to Step 3.

  3. Place them in the C:TFTP-Root directory (or whatever directory you have set as your root TFTP directory).

With the files there, move over to your Cisco device to retrieve the files as you will see

Router1#copy  tftp: flash:
Address or name of remote host []?
Source filename []? c2600-advipservicesk9-mz.123-4.T4.bin
Destination filename [c2600-advipservicesk9-mz.123-4.T4.bin]?
Accessing tftp://
Loading c2600-advipservicesk9-mz.123-4.T4.bin from (via FastEtherne
t0/0): !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
[OK - 23134968 bytes]
23134968 bytes copied in 102.648 secs (225382 bytes/sec)

After you copied the image to your Cisco device, you will need to choose a boot image. With the new IOS file set as the boot image, you can continue the boot process with the new IOS file. Voilá! System upgraded.

If you have enough storage space on your device, you can also do this process with the router running, and using the ROM Monitor mode, which is a small OS that is used to load the IOS image.

After you have completed the upgrade and are sure that everything is working correctly, you can delete any old IOS images that you no longer need. This frees up space on Flash memory for future upgrades.

It is often a good idea to keep your last image around for a while until you are sure there are no major issues with the new IOS. You can also use this image for troubleshooting or diagnostics. Do not forget, before you delete the image, you can copy it to your TFTP server so that you can reload it later.