- SPF :white_check_mark: - DKIM - DMARC https://petermolnar.net/howto-spf-dkim-dmarc-postfix/ - https://www.dmarcanalyzer.com/spf/checker/ - https://www.dmarcanalyzer.com/dkim/dkim-check/ - https://www.dmarcanalyzer.com/dmarc/dmarc-record-check/ Gmail Specific Utilities - https://support.google.com/mail/answer/81126#authentication - https://support.google.com/mail/answer/6227174 - https://postmaster.google.com/u/1/managedomains?pli=1
