I operate DNS from two Virtualmin Servers separate from our Virtualmin web servers. Form submissions from various websites are beginning to be rejected for DMARC - failure to use SPF or DKIM validations. I think we would like to make SPF entries in the master zone files thereby providing the server IP address from which a SendMail might emerge along with the standard email server e.g. mail.yourdomain.com
If you agree with my tactic, could you please provide a format example for the SPF entry at the domain zone file level?
Or, am I better doing this at the Virtual Server level, domain by domain?