SPF, DKIM, and DMARC are three complementary DNS-based email authentication protocols used to verify senders, protect against spoofing, and prevent phishing. If your email service provider has not set up for your domain automatically and properly, various email sending and receiving problems may arise. For example, as of this time, DreamHost does not set up a DMARC record by default for the domain that hosts email on its platform. Instead, one has to explicitly create a TXT record in DNS settings to address potential email issues as more and more service providers are tightening the authentication on email traffic.