Add SPF record to DNS

These days many mailservers are requiring reverse DNS (rDNS) and SPF records to validate the sender from this domain.

How does SPF work:

SPF is easy to understand. The “Internet” uses DNS (Domain Name System) to resolve Domain Names (as an example www.msexchange.org) into IP addresses. DNS is also used to direct requests for different services like e-mail and Web Servers. For every Domain around the world an MX (Mail Exchanger) record must exist. An MX record tells the e-mail sender where the target server for receiving mail is located.

SPF is publishing “reverse MX” records in DNS which tells the mail sender which machines send mail from the domain.

The recipient of the e-mail can now check these records to ensure that e-mail is coming from a “trusted” sender from this domain.

These “reverse MX” records can be easily published in DNS. It takes only one line in DNS to fullfil all requirements.

Microsoft has come up with a good and easy wizard (webpage not downloadable tool) that asks a few questions and spits out the correct SPF.

How to add SPF file to Windows Server DNS – link

OpenSPF Website – link or old site