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Creating a CSR

To apply for an SSL certificate from a provider, you must first create a Certificate Signing Request (CSR for short), which is a request to register a certificate with a certification authority such as Sectigo.

The CSR is technically essential because, amongst other things, it contains the following data:

  • Names of the addresses to be secured
  • Ordering party
  • Encryption method

Generation​

When you order an SSL certificate from centon GmbH, we take care of generating the CSR for you.
See our SSL offers

To generate a CSR request, you will need a command line. However, you can also generate a CSR request via WebPanel or the Plesk management interface:

First of all, we need a new private key. If you haven’t generated one yet, you can create one here:

openssl genrsa -out hauptdomain.de.key 4096

Next, create a text file. This is required to generate a Certificate Signing Request (CSR):

YOURTEXTFILE.txt

[req]
req_extensions = v3_req
distinguished_name = req_distinguished_name
prompt = no
[req_distinguished_name]
C = DE
ST = B
L = BERLIN
O = Musterfirma AG
OU = Technik Abteilung
CN = www.hauptdomain.de
[v3_req]
keyUsage = keyEncipherment, dataEncipherment
extendedKeyUsage = serverAuth
subjectAltName = @alt_names
[alt_names]
DNS.1 = www.hauptdomain.de
DNS.2 = hauptdomain.de

Customise the individual fields to suit your requirements.
Please note, however, that the CN= and DNS.1 should be identical. If you require additional domain names for your certificate, you can extend the [alt_names] list as required by increasing the counter by 1 for each additional domain name.

Tip: Most SSL certificates include coverage for hauptdomain.de and www.hauptdomain.de! Exception: multi-domain certificates

You can now use the private key and the text file you have just created to generate the CSR:

openssl req -new -config IHRETEXTDATEI.txt -out hauptdomain.de.csr -key hauptdomain.de.key

Now submit the required files to the certification authority so that the public key can be generated.

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