Spf and dkim is now a permanent feature that we have had to implement, so we will follow the standards imposed by Aol, Google, Hotmail and Yahoo. We may not always agree with their methodology as we believe it only benefits them and no one else.
What is SPF?
An SPF record is a type of Domain Name Service (DNS) record that identifies which mail servers are permitted to send email on behalf of your domain. The purpose of an SPF record is to prevent spammers from sending messages with forged From addresses at your domain. ( Quote by Google )
What is DKIM?
DomainKeys Identified Mail (DKIM) allows senders to associate a domain name with an email message, thus vouching for its authenticity. This is done by "signing" the email with a digital signature, a field that is added to the message's header. ( Quote by Google )
What is Dmarc?
We will implement shortly to supplement SPF and DKIM.