This generates a 4096-bit SSL-Certificate-Request for the domain ssl.axxeo.de.

openssl req -new -nodes -keyout ssl.axxeo.de-2013.key -out ssl.axxeo.de-2013.csr  newkey rsa:4096

Generating a 4096 bit RSA private key …………………………….
……………………………………………………….++ …..
………………………………………………………………
….++ writing new private key to ’ssl.axxeo.de-2013.key‘ —–

You are about to be asked to enter information that will be incorporate
into your certificate request. What you are about to enter is what is
called a Distinguished Name or a DN. There are quite a few fields but
you can leave some blank For some fields there will be a default value,

If you enter ‚.‘, the field will be left blank.

Country Name (2 letter code) [AU]:DE
State or Province Name (full name) [Some-State]:Niedersachsen
Locality Name (eg, city) []:Hannoversch Münden
Organization Name (eg, company) [Internet Widgits Pty Ltd]:axxeo GmbH
Organizational Unit Name (eg, section) []: Common Name (eg, YOUR name) []:ssl.axxeo.de
Email Address []:domains@axxeo.de

Please enter the following ‚extra‘ attributes to be
sent with your certificate request A challenge
password []: An optional company name []:

You need to enter Country Name, State or Province Name,
Locality Name, Organization Name, Common Name, Email Address

For hardening your webserver, see https://hynek.me/articles/hardening-your-web-servers-ssl-ciphers/

OpenSSL