Email Forwarding and SPF Issues: What You Need to Know

What is SPF?
SPF stands for Sender Policy Framework, an important protocol used to verify the authenticity of emails and protect against spoofing. It is a crucial part of email security and helps reduce phishing attempts.

With SPF, a domain owner can provide specific information about which mail servers are authorized to send emails on behalf of their domain. When an email is received, the receiving mail server checks the SPF records of the sending domain to verify whether the sending server is legitimate.

In short, SPF acts as a kind of 'passport' for emails, allowing recipients to verify whether the sender is truly authorized to send emails on behalf of a specific domain. This reduces the likelihood of deceptive practices and contributes to a safer email environment.

How SPF Works
SPF works as a mechanism to validate the authenticity of emails and prevent spoofing. The process works as follows:

1. SPF Records: Domain owners define SPF records in their DNS settings. These records contain information about which servers are authorized to send emails on behalf of the domain.

2. Sending Email: When a sender sends an email, the SPF record indicates which mail servers are authorized to send that specific email on behalf of the domain.

3. Receiving Mail Server Checks SPF: When the email arrives at the receiving mail server, it checks the SPF record of the sending domain. It compares the IP address of the sending server with the authorized IP addresses in the SPF record.

4. Result of SPF Check:

   • If the IP address matches, the email is considered legitimate and is delivered.
   • If there is no match, the receiving server may choose to flag the email as suspicious or even reject it, depending on the SPF configuration.

Email Forwarding and SPF
Unfortunately, SPF has its drawbacks, one of which is that it can break email forwarding. When you forward an email to another (external) address, the sender of the message is altered to the last server in the chain. This server is not typically listed in the SPF of the sending domain. As a result, the email will not be accepted by the incoming spam filter when it checks SPF. However, emails forwarded to the same domain will still be accepted, provided that the SPF is correctly configured.

What Does This Mean for You?
Be cautious when using email forwarding. This article is designed to make you more aware of email forwarding and when to apply it. If you are unsure about setting up email forwarding, please contact our customer service team. We are happy to assist you.