Verify Cisco IOS Images Checksum with MD5 File Validation

MD5 File Validation on Cisco Router

The MD5 File Validation feature provides a mechanism for users to verify that Cisco IOS image files on Cisco Devices are not corrupted or incomplete. This feature uses the industry-standard MD5 algorithm for improved reliability and security. It’s always advisable to check the MD5 checksum after you downloaded the new IOS image and again after you uploaded the new image to the Cisco device. Otherwise, your Routers may not even able to bootup with corrupted images.

There are free MD5 checksum program available on the Internet. One such program is the MD5 Checker. And it’s also probably good idea to store the MD5 value alongside with the image. Run MD5 file validation for Cisco IOS, It computes and displays the MD5 values, note down the MD5 values before uploading into Cisco device.

How to Verify Cisco IOS Images Using the MD5 Algorithm on Cisco Router

The MD5 File Validation feature can only be used to check the integrity of a Cisco IOS software image that is stored on a Cisco IOS device. It cannot be used to check the integrity of an image on a remote file system or an image running in memory.

Verifying Cisco IOS Image

Once you have uploaded the new Cisco IOS image and before you reload the Router, run this command:

Cisco-Router>enable
Cisco-Router#verify /md5 filesystem:filename
or
Cisco-Router#verify /md5 filesystem:filename md5-value

The MD5 File Validation feature allows you to generate the MD5 checksum for the Cisco IOS image stored on your router and compare it with the previous MD5 value to verify that the image on your router is not corrupted. If both MD5 values are same, Cisco IOS image not corrupted, you can reload Cisco device to boot with new IOS image. If both MD5 values are not matched, try to check once again both MD5 values or upload Cisco IOS once again.

Example : Verify Cisco IOS Image on Cisco 2811 Router

Cisco-Router#verify /md5 flash:c2800nm-advipservicesk9-mz.150-1.M3.bin

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………………………….Done!

verify /md5 (flash:c2800nm-advipservicesk9-mz.150-1.M3.bin) = 5bd82bd4e62ce774627dfc2e5db9deb2

Cisco-Router#

Example : Verify Cisco IOS Image on Cisco 1841 Router

Cisco-Router#verify /md5 flash:c1841-adventerprisek9-mz.124-21.bin

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………………………….Done!

verify /md5 (flash:c1841-adventerprisek9-mz.124-21.bin) = 7de9271b4a477143ceae0c842dd27118

 

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  1. Dana says:

    Appreciation pro this article. This is benefited for me to verify Cisco IOS files with MD5 file validation.

  2. Tony says:

    You really make it appear so easy with your presentation however I to find this topic to be actually something that I need.

  3. Samuel says:

    Thanks for sharing, It is useful for every one to verify Cisco ios image after upload in to any Cisco devices.

  4. Krish says:

    We must do the Cisco IOS image verification after uploaded any new IOS. This really helpful for me and for every network engineer. Thanks…….

  5. Navin says:

    Great article ! This is is very useful to validate with MD5 checksum before booting with newly uploaded Cisco IOS Images on Cisco Router or Switch..

    Thanks

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