My txt entry for my domain is as follows:
"v=spf1 a ip4:aspmx.googlemail.com ptr:aspmx.googlemail.com include:aspmx.googlemail.com -all"
I have also tried to use ptr
in addition to a
. However, I'm not sure I fully understand the difference between them. PTR seems to do a reverse lookup on the domain, whereas A simply references the A record in the zone file?
The header response from Gmail is:
Received-SPF: unknown (google.com: domain of do-not-reply@example.com uses a mechanism not recognized by this client. unknown mechanisms: ))
Authentication-Results: mx.google.com; spf=permerror (google.com: domain of do-not-reply@example.com uses a mechanism not recognized by this client. unknown mechanisms: )) smtp.mail=do-not-reply@example.com; dkim=neutral (no key) header.i=@example.com