E-mail address for Certificate Signing Request

Should an e-mail address in a Certificate Signing Request (CSR) for a server with a domain name aaa.bbb.ccc.ddd contain exactly all domain zones or it can be [email protected] (in other words, just an organizational top-level domain)?

Context: I'm relying on this guide, but the installation will be done on a private cloud, not Linode.

Solution 1:

The email address in the request doesn't need to relate to the DNS names in the certificate at all. It could be a gmail address if you wanted. It's just metadata and a hypothetical way for someone to contact the owner of an SSL protected site. Technically it's not even required metadata. It's completely up to the Certificate Authority whether they want to require it or not. Though some Certificate Authorities do use the e-mail address field to verify that you can receive email on that domain.