Validate IOS Integrity w/ MD5 Checksum
Cisco IOS software command that allows you to check the integrity of a Cisco IOS software image by comparing its MD5 checksum value against a known MD5 checksum value for the image.
Check the Cisco website for the known valid MD5 value from the IOS version you are checking, by hovering over the IOS Image download link. A pop-up will appear and show you detailed information about the software version, including the MD5 Checksum.
You can click on the "clipboard" icon to copy the MD5 value for comparison. See screenshot below:
Now use the "verify /md5 {Location & Filename}" command on the router:
MT_4321#
MT_4321#verify /md5 flash://isr4300-universalk9.16.06.05.SPA.bin
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(Output omitted for brevity)
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...................................................................Done!
verify /md5 (bootflash:/isr4300-universalk9.16.06.05.SPA.bin) = c9c564ec1c39207b065599fe4087884b
MT_4321#
Below I have pasted the copied checksum from Cisco.com in the CLI, for easy comparison to the above checksum output from the router.
MT_4321#c9c564ec1c39207b065599fe4087884b