How to Validate that You Control a Domain for an SSL Certificate (DCV)

by DNS Record

Validation by DNS record implies that you have access to the DNS record management of your domain (whether or not at Gandi), and can add a CNAME record to it.

Validation by Email (recommended) 

Create the email address “admin@example.com” and you will receive an email with a link to click.

You could add an alias but it could be filtered as spam and you won’t receive it.

Validation by File

This validation method requires that you have access to the web server that hosts the website that the domain will point to.

You are asked to copy a TXT file that contains a verification key, and to place it at the following location on your domain. You will replace www.example.com with the domain you want to secure, and replace filename with the name of the file you are provided.

http://www.example.com/.well-known/pki-validation/filename.txt

The file must be placed at every full domain you want covered by a certificate. This means if you want both www.example.com and example.com (the bare domain without www) you must place two files; one using www.example.com and one using only example.com.

Beware of CMS installations (such as Wordpress, for example) which can block access to any “off-site” file.