Authenticate email with DKIM
Generate the domain key
To generate the domain key used to sign mail:
- Sign in to the Google Admin console.
- Click Apps > Google Apps > Gmail > Authenticate email.
- Select the domain for which you want to generate a domain key.
The name of your primary domain appears by default. To generate a domain key for a different domain, select it from the drop-down list.
- Click Generate new record.
- Optionally, update the text used as the DKIM selector prefix.
The selector prefix is used to distinguish the domain key that Google Apps uses from any other domain keys you may have. In most cases, you'll select the default prefix "google". The only reason to change the prefix is if your domain already uses a DKIM domain key with the selector prefix "google".
- Click Generate.
The text box displays the information you need in order to create the DNS record that recipients query in order to retrieve the public domain key. Please note, keys generated through the Admin console are 2048 bit in strength.
Next: Update DNS records