Service Manual

Using Hashes to Validate Software Images

You can use the MD5 message-digest algorithm or SHA256 Secure Hash Algorithm to validate the software image on the ash

drive, after the image has been transferred to the system, but before the image has been installed. The validation calculates a hash

value of the downloaded image le on system’s ash drive, and, optionally, compares it to a Dell Networking published hash for that

le.

The MD5 or SHA256 hash provides a method of validating that you have downloaded the original software. Calculating the hash on

the local image le, and comparing the result to the hash published for that le on iSupport, provides a high level of condence 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, can prevent the installation of corrupted or modied images.

The verify {md5 | sha256} command calculates and displays the hash of any le on the specied local ash drive. You can compare

the displayed hash against the appropriate hash published on i-Support. Optionally, the published hash can be included in the

verify {md5 | sha256} command, which will display whether it matches the calculated hash of the indicated le.

To validate a software image:

1. Download Dell Networking OS software image le from the iSupport page to the local (FTP or TFTP) server. The published

hash for that le is displayed next to the software image le on the iSupport page.

2. Go on to the Dell Networking system and copy the software image to the ash drive, using the copy command.

3. Run the verify {md5 | sha256} [ ash://]img-le [hash-value] command. For example, verify sha256 ash://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 ash drive after the image has been transferred to the system, but before the image has been

installed, use the verify {md5 | sha256} [ ash://]img-le [hash-value] command in EXEC mode.

• md5: MD5 message-digest algorithm

• sha256: SHA256 Secure Hash Algorithm

• ash: (Optional) Species the ash drive. The default is to use the ash drive. You can just enter the image le name.

• hash-value: (Optional). Specify the relevant hash published on i-Support.

• img-le: Enter the name of the Dell Networking software image le to validate

Examples: Without Entering the Hash Value for Verication

MD5

Dell# verify md5 flash://FTOS-SE-9.5.0.0.bin

MD5 hash for FTOS-SE-9.5.0.0.bin: 275ceb73a4f3118e1d6bcf7d75753459

SHA256

Dell# verify sha256 flash://FTOS-SE-9.5.0.0.bin

SHA256 hash for FTOS-SE-9.5.0.0.bin:

e6328c06faf814e6899ceead219afbf9360e986d692988023b749e6b2093e933

Examples: Entering the Hash Value for Verication

MD5

Dell# verify md5 flash://FTOS-SE-9.5.0.0.bin 275ceb73a4f3118e1d6bcf7d75753459

MD5 hash VERIFIED for FTOS-SE-9.5.0.0.bin

Getting Started