SPF

check-auth@verifier.port25.com

"v=spf1 include:aspmx.googlemail.com ~all"

"v=spf1 a mx ~all"

"v=spf1 a mx ip4:seu-ip ~all" "v=spf1 a mx ip4:104.131.231.178 include:aspmx.googlemail.com ~all"

http://www.meuspf.com/check http://mxtoolbox.com/spf.aspx http://www.meuspf.com/ http://www.blogdohost.com.br/como-criar-um-registro-spf/ http://www.antispam.br/admin/spf/ https://support.google.com/mail/answer/81126 https://support.google.com/mail/contact/msgdelivery