DMARC alignment refers to the relationship between the domains in an email's "From" field and the domains in the email's authentication results (SPF & DKIM). With DMARC, domain owners can specify that the "From:" address in an email message must be aligned with the domain used in the SPF and DKIM checks. In other words, if a message is sent from "email@example.com", the SPF check must pass for "example.com", and the DKIM check must pass for the "d=" domain that is specified in the DKIM signature. This helps to prevent attackers from using forged "From:" addresses to bypass SPF and DKIM checks. By requiring alignment between the "From:" address and the domains used in SPF and DKIM, DMARC provides an additional layer of protection against spam and phishing attacks. It helps to ensure that email receivers can trust the identity of the sender and can confidently filter out messages that do not pass DMARC evaluation.