DNS SPF Record Example For MailChimp, GSuite, On-Premises

dns-sender-policy-framework-example.txt

; SPF (Sender Policy Framework) is an email authentication protocol 
; that allows the owner of a domain to specify which mail servers they use to send mail from that domain.
;
; explanation
; https://postmarkapp.com/blog/explaining-spf 
;
; mailchimp                     include:servers.mcsv.net        https://mailchimp.com/help/set-up-custom-domain-authentication-dkim-and-spf/
; gmail                         include:_spf.google.com         https://support.google.com/a/answer/33786?hl=en
; on-premises mail              ip4:x.x.x.x/24             

@        IN      TXT     "v=spf1 a mx ip4:x.x.x.x/24 include:servers.mcsv.net include:_spf.google.com ~all"

; A SPF record is required for each sudomains

*.example.com   IN      TXT     "v=spf1 a mx ip4:x.x.x.x/24 include:servers.mcsv.net include:_spf.google.com ~all"