Supermicro IPMI SSL TLS Certificate Replacement

I’ve been meaning to replace the SSL/TLS certificates on my Supermicro servers IPMI (Intelligent Provisioning Management Interface) consoles. Now that I’ve upgraded the firmware on both units I think it’s about time I sorted the certificates as well. This is something I did at work some time ago and then handed over to our team junior to complete. Anyone I work with will tell you that I really do hate seeing certificate alerts!

Let’s get right to it – once logged on we can click the ‘Configuration’ button and then select the ‘SSL Certification’ option.

Configuration SSL Certification Menu

The system requires we provide the new certificate and the private key, it would be nice if Supermicro provided a built-in certificate creation and signing request interface. It’s not the end of the world that they don’t but it would simplify things.


I will generate a private 2048 bit RSA key and redirect the output from OpenSSL to a file named ‘node1impi.key’, I strongly recommend you do not create a key size less than 2048 bits.

C:\OpenSSL\bin>openssl.exe genrsa 2048 > node1ipmi.key
Generating RSA private key, 2048 bit long modulus
e is 65537 (0x010001)



Now I have my private key it’s time to create my configuration file so I can then combine the two to generate my certificate signing request, also known as a CSR. For this example I’m just going to re-use an existing template I have, modifying the common name. I’ll save this text file as ‘node1ipmi.cfg’. Be sure to use SHA256 as a minimum for the hashing algorithm.

[ CA_default ]
 default_md    = sha256

[ req ]
 default_bits = 2048
 distinguished_name = req_distinguished_name
 encrypt_key = no
 prompt = no
 string_mask = nombstr
 req_extensions = v3_req

[ v3_req ]
 basicConstraints = CA:FALSE
 keyUsage = digitalSignature, keyEncipherment, dataEncipherment
 extendedKeyUsage = serverAuth
 subjectAltName = @alt_names

 DNS.2 =

[ req_distinguished_name ]
 countryName = GB
 stateOrProvinceName = London
 localityName = London
 0.organizationName = ByteSizedAlex Corporation
 organizationalUnitName = IT Services
 commonName =
 emailAddress = [email protected]


We now feed OpenSSL the configuration and private key files and instruct it to output a new CSR.

C:\OpenSSL\bin>openssl.exe req -out node1ipmi.csr -key node1ipmi.key -new -config node1ipmi.cfg


The next step is to submit the CSR to your certificate authority (CA) – of course the instructions here depend entirely on your own CA setup so I’ll move on to importing the files to the IPMI console.

Once you have the required files you will need to ensure the certificate ends with a .cert or .pem extension and the private key file has a .pem extension.

Upload Certificate and Private Key

Certificate Replacement Warning

Once confirmed the system will prompt for a reset of the IPMI interface.

Certificate Uploaded Reset Required


Allow the system time to complete the reset process. If all is well your broswer should no longer dispaly an insecure/warning message and we can celebrate the joyous green. I am happy to see that Chrome reports Supermicro support modern ciphers on their IPMI interfaces, or at least on my version with the latest firmware.

Secure Website Confirmation

A quick nmap scan seems to suggest the following cipher suites are supported, I haven’t been able to find any definitive documentation though so take this with a pinch of salt.

  • TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (secp256r1)
  • TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 (secp256r1)
  • TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 (dh 1024)
  • TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 (dh 1024)
  • TLS_RSA_WITH_AES_256_GCM_SHA384 (rsa 2048)
  • TLS_RSA_WITH_AES_256_CBC_SHA256 (rsa 2048)
  • TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (secp256r1)
  • TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 (secp256r1)
  • TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 (dh 1024)
  • TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 (dh 1024)
  • TLS_RSA_WITH_AES_128_GCM_SHA256 (rsa 2048)
  • TLS_RSA_WITH_AES_128_CBC_SHA256 (rsa 2048)



There are other ways of generating the required certificates and deploying to Supermicro systems but this works perfectly fine for me and my small lab setup. Hopefully it will prove useful to anyone in a similar situation.

20 thoughts on “Supermicro IPMI SSL TLS Certificate Replacement”

  1. Sorry for kinda necro-posting; I’m facing the problem here that the device allows uploading, displays the correct SSL certificate expiration date…
    Sadly, after the reboot it comes back with some self signed certificate…

    • Have you tried flushing your browser cache/using an alternate browser just to rule that out? Also you could do a reset on the IPMI controller first then complete the change to see if that assists. I assume you’re running the latest firmware version as potentially it could be a bug too.

  2. Great post. I am having an issue getting the entire certificate chain installed. When I browse to the management IP I see Cert error chain not complete and does not display the Intermediate cert, even though the file used for the installation includes the server cert and intermediate cert. Any thoughts?.

    • Hi Andres,

      First off thanks for the kind words, always nice to get positive feedback! When you open the certificate file on your computer does it show the complete chain correctly on the ‘Certification Path’ tab? If you could let me know what shows there and give me a bit more info on what you’ve done so far that would be great. I’m sure we can get to the bottom of the problem.


  3. I installed my own ones. no issue reported during install. Alas, the web server stopped working.
    – upgrade to latest firmware (3.72)
    – reset via ipmicfg -fd
    but the web server seems not to be working anymore.
    but BMC is reachable and pretty manageable via IPMIVIEW.

    Any suggestion ?


    • Hi Ivan,

      Sorry to hear you are having problems. I wonder, have you tried doing a BMC reset with IPMITool? An example is below, this is from memory and you might want to perform with the system in maintenance –

      ipmitool mc reset cold -H ipAddressHere -U username -P password

      I have had some luck in the past with a complete power off, removing all power leads and letting the capacitors drain out. I don’t recall having the same problem as you describe but that might help if the above reset doesn’t. Let me know how you get on, hopefully we can come to a resolution.



  4. Hi Alex,

    I did not try ipmitool, gonna try out shortly; I guess IPMICFG should do the same but seems not to work. will try ipmitool.

    I tried to remove powercord and detach RTC battery for a couple of minutes but it seem to retain conf somewhere in flash.

    Gonna perform some more testing and get back to you.

    thank you for the suggestions.


  5. Apologies if I am being thick here but the 1st cmd generates the file node1ipmi.key.

    However, when you show the GUI import, for private key, you show Node1ipmi.pem

    Where does that file come from?

    • Hi Mike,

      If you check the section after submitting the config and private key files to OpenSSL and then to your CA, I mention the need to ensure the files have the correct extensions. Just above the screenshot I think you’re referencing. Let me know if you have any trouble and I’ll try and assist further.

  6. So I have to sign the certificate (server.csr) that’s created by the openssl command against our Company signed certificates. This gives me a cert.pem file.

    I am struggling to then use this cert.pem as a valid certificate – IPMI tools barfs stating the private key and cert don’t match!!!

    • Just to make sure I’ve got your workflow down correctly –

      -> You’re creating a private key using the OpenSSL command
      -> You create a config file similar to the one I use as an example
      -> You pipe the above private key and config file through OpenSSL to generate a CSR
      -> You submit the CSR request to (presumably) internal certificate authority – this generates your signed cert which you then save
      -> You select the private key and the new cert.pem for upload and the interface refuses to accept these files

      The last point might be incorrect – are you saying that the interface allows you to upload the files but remote tools do not like the certificate? If it accepted them and restarted fine I’d expect the webpage to display the correct certificate without errors. Let me know if I’ve misunderstood, I’m sure we can figure it out.

        • I’ve run through the steps again on a test system and I’m not able to reproduce your issue at this time. If I pick the wrong private key then I can generate the problem but otherwise it’s working for me with the kit I have.

          I’m presuming you’ve tested with a fresh private key/config and submitted that to your CA?

  7. Yes I have . I think the problem is the key that I get (cert.pem) is where the issue lies.Even though this cert.pem is created using the server.csr generated from the private key, it’s still not liking the combination when imported in to the WebUI.

    SSL certificate validation failed. Please try to upload the certificate and key again.

    NOTE: The cert.pem starts/finishes with:


    The private key starts/finishes with:


    If I try to “validate” the cert.pem, I get the following:

    openssl req -noout -text -in cert.pem
    unable to load X509 request
    139851323561808:error:0906D06C:PEM routines:PEM_read_bio:no start line:pem_lib.c:703:Expecting: CERTIFICATE REQUEST

    I also tried to follow another guide and run this command too but it errors:

    openssl x509 -x509toreq -days 365 -in cert.pem -signkey server_key_3.pem -out ca.req
    unable to load certificate
    140394197907280:error:0906D06C:PEM routines:PEM_read_bio:no start line:pem_lib.c:703:Expecting: TRUSTED CERTIFICATE

    • Hmm I think when you’re validating that cert.pem you’re actually asking OpenSSL to validate a CSR file. I’d guess if you pointed that at the CSR it would load it fine. I have to say I’m not an expert with OpenSSL so I could be wrong in that assumption.

      I’ll see if I can find another text box to try this out on. What firmware version are your systems running?

  8. I tried following the guide but it tells me “SSL certificate validation failed. Please try to upload the certificate and key again.”

    How is it trying to validate the certificate? Is it trying to connect to the internet? I just want to be able to access this without it telling me it’s not secure.

  9. I successfully installed a certificate and file, but when I go to the URL using the DNS name on the certificate I get a 400 Bad request message. any thoughts on what is causing that message and how to get past it?

  10. I had the same problem and resetting, factory defaulting the BMC etc did nothing. After months of searching I eventually found the raw command to set the SSL certificate back to the default which brought the web web server back from the dead.

    ipmicfg -raw 0x30 0x68 0 0

    I still have no idea what broke it but I suspect key length (3072 bits), digest (sha512) or the cipher suite.



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