github.com/albertito/spf (go): Package spf implements SPF (Sender Policy Framework) lookup and validation.  Sender Policy Framework (SPF) is a simple email-validation system designed to detect email spoofing by providing a mechanism to allow receiving mail exchangers to check that incoming mail from a domain comes from a host authorized by that domain's administrators [Wikipedia].  This is a Go implementation of it, which is used by the chasquid SMTP server (https://blitiri.com.ar/p/chasquid/).  Supported mechanisms and modifiers:  References:
Keywords: go-library|smtp-server|spf|spf-library|spf-record