Domain owners using SPF publish a TXT record that indicates which machines are permitted to send emails in their domain's name. The SPF checks performed by receiving mail servers use the published list of authorized hosts to determine if a given mail can be accepted as from the claimed sender or not.
FastMail can help you configure SPF to protect your domain from email spoofing. If your domain is hosted with another provider, we suggest you contact them for instructions on how to correctly configure these.
Setting Up SPF for FastMail
If you're not using FastMail to host your domain, you'll need to configure SPF records on your domain's DNS. To do so:
Login to your DNS management console
Navigate to Tools & Settings > DNS Template
You need to edit the DNS TXT record related to SPF
An SPF TXT record for FastMail will have the following syntax:
yourdomain.com TXT v=spf1 include:spf.messagingengine.com -all
Publish this record in your DNS records section for your respective domain.
Note: If you don’t have an SPF record previously for your domain, simply publish the above-mentioned record to enable SPF for outgoing emails using FastMail. If you do have an existing SPF record in your DNS, you need to modify it to include FastMail, as shown below:
Previous SPF record: v=spf1 mx -all
Modified SPF record: v=spf1 mx include:spf.messagingengine.com -all
Wait for 24-48 hours to allow your DNS to process the changes