If this was created for intranet then you can also create your own CA certificate or CA certificate chain and use these CA to sign and generate your server certificates. If your CSR shows all the hostnames then that should be sufficient for creating a SAN certificate. Openssl sign csr with subject alternative name. Thanks to all our readers for all the hints, ideas and suggestiong they gave me to improve this post, which apparently is still very useful to a lot of System Administrators out there. The first screenshot is just an example to understand how companies like Facebook is also using SAN for their certificates. How to Duplicate a Certificate with Subject Alternative Names (SANs) On the server for which you want the duplicate Wildcard Certificate with SANs, create a new CSR/keypair. These certificates generally cost a little bit more than single-name certs, because they have more capabilities. If you are not familiar with these parameters then I suggest you to read beginners guide to understand all certificate related terminologies used with openssl and openssl configuration file, If you prefer to manually enter the CSR details such as Country, State, Common Name etc then you can use this configuration file. Next we will use openssl to generate our Certificate Signing Request for SAN certificate. Ah, did not read the link. Next, we will generate CSR using private key above AND site-specific copy of OpenSSL config file. By adding DNS.n (where n is a sequential number) entries under the “subjectAltName” field you’ll be able to add as many additional “alternate names” as you want, even not related to the main domain. Generate a private key and Certificate Signing Request by using the sancert.cnf configuration file. openssl req -text -noout -in private.csr You should see this: X509v3 Subject Alternative Name: DNS:my-project.site and Signature Algorithm: sha256WithRSAEncryption. I have not assigned any passphrase to the private key, you can also use -des3 encryption algorithm to add a passphrase to your private key, We will not use the complete /etc/pki/tls/openssl.cnf instead we will create our own custom ssl configuration file with required parameters only. When you request a SAN certificate, you have the option of defining multiple DNS names that the certificate can protect. Create the OpenSSL Private Key and CSR with OpenSSL. We’re software developers, design thinkers, and security experts. Linux, Cloud, Containers, Networking, Storage, Virtualization and many more topics. For example: Let’s take a look at a real-time example of skype.com, which has many SAN in a single certificate. The Subject field with all values: The SubjectAltName field with all values: Export CSR using the Java keytool. @EddieJennings said in OpenSSL CSR with Subject Alternative Name: @JaredBusch Correct. Resolution The following solution details steps to create a CSR with the SAN extension using a … Making an openssl ca -policy policy_anything -out server.example.com.crt -infiles So by using the common syntax for OpenSSL subject written via command line you need to specify all of the above (the OU is optional) and add another section called … October 30, 2014. Now since you have your Certificate Signing Request, you can send it to Certificate Authority to generate SAN certificates. By adding DNS.n (where n is a sequential number) entries under the “subjectAltName” field you’ll be able to add as many additional “alternate names” as you want, even not related to the main domain. more openssl-csr.conf [ req ] default_bits = 2048 distinguished_name = req_distinguished_name req_extensions = req_ext [ req_distinguished_name ] countryName = GB stateOrProvinceName = Cambs localityName = Peterborough organizationName = Net Assured Limited commonName = Common Name (e.g. # openssl req -noout -text -in ban21.csr | grep -A 1 "Subject Alternative Name". Here replace server.cert.pem with your server certificate. The command below will export the Certificate Signing Request (CSR) into myserver.csr file. 4.When prompted, enter the appropriate information. Create a Certificate Signing Request (CSR) "openssl req -newkey rsa:2048 -keyout server_key.pem -out server_req.pem" Review the CSR to verify the Subject Alternative Name has been added as expected "openssl req -text -in server_req.pem" openssl req -new -key wikiCERT-key.pem -out certificate.csr -config opensslWiki.cnf Since we have used prompt=no and have also provided the CSR information, there is no output for this command but our CSR is generated, Next verify the content of your Certificate Signing Request to make sure it contains Subject Alternative Name section under "Requested Extensions". After generating a certificate out of it, the certificat doesn't show any of these entries (like in your first screenshot) If you forget it, your CSR won’t include (Subject) Alternative (domain) Names. Posted on 02/02/2015 by Lisenet. Verify CSR Openssl sign CSR with Subject Alternative Name Next use the server.csr to sign the server certificate with -extfile using Subject Alternative Names to create SAN certificate I am using my CA Certificate Chain and CA key from my previous article to issue the server certificate My Code Of course you can use your text editor of choice, I used HEREDOC mostly because it shows better through blog posts in my opinion. Please note -config switch. $ cat << EOL > san.conf [ req ] default_bits = 2048 default_keyfile = san.key #name of the keyfile distinguished_name = req_distinguished_name req_extensions = req_ext [ req_distinguished_name ] countryName = Country Name (2 letter code) countryName_default = … For instructions on how to create a CSR, see Create a CSR (Certificate Signing Request). This need is due to the fact that some certificate providers (like GeoTrust) don’t cover the parent domain when requesting a new certificate (eg: CSR for www.endpoint.com won’t cover endpoint.com), unless you specifically request so. Values must be prefixed by their options. In this tutorial I gave you an overview on SAN certificates, and the steps to create Certificate Signing Request for SAN certificates using openssl in Linux. Now, if you want to include all those SANs, then the openssl.cnf you used to sign will have to have all those SANs already defined. Creating and signing an SSL cert with alternative names , Signing an existing CSR (no Subject Alternative Names). 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Subject Alternative Name (SAN) extension to attach to the certificate signing request. We design and build custom software solutions. And while that’s usually fun and interesting, there’s one thing I often needed and never figured out, till a few days ago, which is how to generate CSRs (Certificate Signing Requests) with AlternativeNames (eg: including www and non-www domain in the same cert) with a one-liner command. You must keep your private key safely as this CSR will only work with this private key. First of all we need a private key. Create a Subject Alternative Name (SAN) CSR with OpenSSL. Solved: Hi, Using Splunk (v6.5.0) on Windows Server 2008 R2 Datacenter, trying to generate CSR files using the built-in openssl via PowerShell This single certificate can be installed on a web server and used to validate traffic for any of the DNS names that are contained in the certificate. In the Lab - OpenSSL. keytool -certreq -keystore server.jks -storepass protected -file myserver.csr Take-aways Enter Name & Description Select DNS with *.aventislab.com – this will be the SAN (Subject Alternative Name) included in our SSL Certificate Change the Key Size to 2048 and Check Make Private Key Exportable Enter C:\temp\aventislab.req to export the CSR File First up, let’s have a look at the CSR and see what SANs were requested; openssl req -text -noout -verify -in server.example.com.csr. To try this in the lab, we create a CSR using OpenSSL by creating a config file to be referenced by the openssl req command which can generate a key pair and Certificate Signing Request (CSR) with the WSANs included as shown below: Generate the certificate. You are welcomed to send the CSR to your favorite CA. To create a Certificate Signing Request (CSR) and key file for a Subject Alternative Name (SAN) certificate with multiple subject alternate names, complete the following procedure: Create an OpenSSL configuration file (text file) on the local computer by editing the fields to the company requirements. For example have a look at the certificate of. Generate a private key: $ openssl genrsa -out san.key 2048 && chmod 0600 san.key. 1.Login to Linux server where the OpenSSL utility is available. So here’s an example to generate a CSR which will cover *.your-new-domain.com and your-new-domain.com, all in one command: To be honest, that’s a sub-optimal solution for a few reasons but mostly that it’s not comfortable to fix in case you did a typo or similar. Note: in the example used in this article the configuration file is the only method get... Instead of the -sha256 option to enable SHA256 Signing instead of the -sha256 option enable. 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