Follow the below steps to verify the integrity of the IOS software on Cisco IOS routers.
- Confirm the current IOS image the router is using to boot.
router#show version
<omited>
System image file is "flash0:c3900-universalk9-mz.SPA.153-2.T.bin"
<omited>
- Log into Cisco website and find the IOS image. Mouse over to get the MD5 checksum
- Issue verify command with hash from Cisco’s website. If you don’t enter the hash, the router’s IOS hash will be displayed for manual verification.
verify /md5 flash0:c3900-universalk9-mz.SPA.153-2.T.bin 7727d9c4daa89d62bb2ff6bdb0905feb
- Router’s output if the IOS hash has been matched.
Verified (flash0:c3900-universalk9-mz.SPA.153-2.T.bin) = 7727d9c4daa89d62bb2ff6bdb0905feb
- If the hash did not match, the following will be displayed.
%Error verifying flash0:c3900-universalk9-mz.SPA.153-2.T.bin
Computed signature = 7727d9c4daa89d62bb2ff6bdb0905feb
Submitted signature = 7727d9c4daa89d62bb2ff6bdb0905fe