Sender Policy Framework (SPF) is used to authenticate the sender of an email. With an SPF record in place, Internet Service Providers can verify that a mail server is authorized to send email for a specific domain. An SPF record is a DNS TXT record containing a list of the IP addresses that are allowed to send email on behalf of your domain.
SPF has become exceedingly vital to help verify which sending infrastructure can relay email on behalf of your domain. Implementing SPF for email provides major benefits.