To prevent Spammers from spoofing your domain and trying to send email as your domain from another location, you can enable SPF and Domain Keys. The nameservers for your domain must point to those provided in our welcome email. External nameservers are not supported for this setup.
To enable these technologies, login to your cPanel account. Under the mail header, choose Email Authentication.
Once you choose Email Authentication, you will need to click on Enable. The picture below shows that both SPF and Domain Keys are enabled (active) for this domain.
Your SPF records and Domain Keys are now enabled for your domain. It is now harder for anyone to forge email coming from your domain and will certainly reduce back scatter spam attacks.