What is the relationship between SPF, DKIM, and DMARC?

SPF, DKIM, and DMARC are all email authentication protocols that help to prevent email spoofing. SPF allows the owner of a domain to specify which servers are authorized to send an email on behalf of their domain. DKIM allows the sender to digitally sign their emails using a private/public key pair. DMARC allows the owner of a domain to specify which mechanisms (such as SPF and DKIM) are used to authenticate emails sent from their domain and what to do if an email fails authentication.