Digital Forensic Certification Practice Exam

Which email header field prevents sender address forgery and designates servers allowed to send emails for a domain?

1. DKIM

2. MIME

3. SPF

4. Message ID

The correct answer is: SPF

The correct answer is the field that is specifically designed to prevent sender address forgery by defining which mail servers are authorized to send email on behalf of a particular domain. This mechanism is known as Sender Policy Framework (SPF). SPF works by allowing domain owners to publish a list of IP addresses or domain names that are permitted to send email from their domain in their DNS records. When an email is received, the recipient's mail server can check this list to validate whether the email was sent from an authorized source. If the sending server's IP address does not match any of the IP addresses listed in the SPF record for that domain, the email can be flagged as potentially forged or spam. In contrast, while DKIM (DomainKeys Identified Mail) also plays a role in authentication by allowing the sender to sign the email content, it does not specifically designate which servers are allowed to send on behalf of a domain. MIME (Multipurpose Internet Mail Extensions) relates to the format of email messages and does not address forgery prevention. The Message ID is a unique identifier for individual email messages but does not have any bearing on sender authentication or authorization. Understanding SPF helps you recognize the importance of establishing trust in email communications and the technical measures that