Email authentication is important because it addresses one of the fundamental security problems inherent to email sending technology. By exploiting such weaknesses spammers, phishers and spoofers have been able to thrive. Authentication is integral to preventing phishing and other fraud while playing a key role in the emerging reputation and accreditation systems that will drive the future of email. As a legitimate business, authentication is not optional; rather it is essential to securing your brand and online reputation. This paper provides guidelines and recommendations for legitimate businesses seeking to improve their deliverability rates and protect their brand from domain forgery and phishing scams.