Verify Software Images Before Installation - Dell S4048T Configuration Manual

Verify Software Images Before
Installation
To validate the software image on the flash drive, you can use the MD5 message-digest algorithm or SHA256
Secure Hash Algorithm, after the image is transferred to the system but before the image is installed. The
validation calculates a hash value of the downloaded image file on system's flash drive, and, optionally,
compares it to a Dell Networking published hash for that file.
The MD5 or SHA256 hash provides a method of validating that you have downloaded the original software.
Calculating the hash on the local image file and comparing the result to the hash published for that file on
iSupport provides a high level of confidence that the local copy is exactly the same as the published software
image. This validation procedure, and the verify {md5 | sha256} command to support it, prevents the
installation of corrupted or modified images.
The verify {md5 | sha256} command calculates and displays the hash of any file on the specified local
flash drive. You can compare the displayed hash against the appropriate hash published on iSupport.
Optionally, you can include the published hash in the verify {md5 | sha256} command, which displays
whether it matches the calculated hash of the indicated file.
To validate a software image:
1 Download Dell Networking OS software image file from the iSupport page to the local (FTP or TFTP)
server. The published hash for that file displays next to the software image file on the iSupport page.
2 Go on to the Dell Networking system and copy the software image to the flash drive, using the copy
command.
3 Run the verify {md5 | sha256} [ flash://]img-file
example, verify sha256 flash://FTOS-SE-9.5.0.0.bin
4 Compare the generated hash value to the expected hash value published on the iSupport page.
To validate the software image on the flash drive after the image is transferred to the system, but before you
install the image, use the verify {md5 | sha256} [ flash://]img-file
in EXEC mode.
• md5: MD5 message-digest algorithm
• sha256: SHA256 Secure Hash Algorithm
• flash: (Optional) Specifies the flash drive. The default uses the flash drive. You can enter the image file
name.
• hash-value: (Optional). Specify the relevant hash published on iSupport.
• img-file: Enter the name of the Dell Networking software image file to validate
Examples: Without Entering the Hash Value for Verification
[hash-value] command. For
[hash-value] command
Getting Started 66