Note that the posted hashes are for the mz (zipped) images, and these values won't align with the extracted images if you decompress the images keep a copy of both the compressed and uncompressed images. Then check if the SHA512 hash matches, and note that while SHA512 collisions aren't impossible this is considerably more difficult especially while also matching the MD5 and the file-size and being a bootable image with a valid signature from Cisco:Ĭertutil -hashfile sha512 | findstr /v CertUtil Then check if the MD5 hash matches, although note that MD5 collisions are certainly feasible:Ĭertutil -hashfile md5 | findstr /v CertUtil Say you 'found' a copy of that file that you might think is sketchy, what can you do to test this?ĭir /w | findstr File(s) 1 File(s) 56,187,628 bytes It is quite easy to compare an image that might have fallen off the back of a truck to the official source without even needing a account, without having to worry about malware.

The file size and hash(s) are both known and easy to calculate for most any Cisco image. You can find free Cisco dynamips but I would not recommend you to do it beacuse those images could contain malware and other stuff.

Ios images for gns3 free download