Sender Policy Framework
The SPF or Sender Policy Framework is intended to prevent spoofing of sender addresses in emails. Specifically, the sending of emails via unauthorized mail servers is to be prevented.
For this purpose, additional information is stored in the form of an SPF record in the DNS (Domain Name System). This TXT-based SPF entry contains specific information about authorized mail servers.
The receiving mail server can use the domain's SPF record to check whether the email received comes from an authorized mail server or from an unauthorized server. In the latter case, the email can be identified using SPF spam protection and declared as spam.
Abbildung: Wie funktioniert ein SPF-Record?
If an e-mail is delivered to the receiving mail server, it checks which server sent the message.
In the DNS settings of the sending domain, all servers that are authorized to send e-mails can be configured using an SPF record.
If the details of the SPF record match the sender information of the email, the email will be delivered, otherwise it will be treated as SPAM.
Do you need support in creating or optimizing your SPF records or do you want personal advice or error analysis?