Auto-Forwarding

What is Auto-Forwarding in Email?

Auto-forwarding is an email feature that automatically redirects incoming messages from one mailbox to another, based on predefined user or system rules. It’s commonly used to consolidate mail from multiple accounts, forward work messages to personal inboxes, or maintain access continuity during staff transitions. While convenient, auto-forwarding can interfere with DMARC, SPF, and DKIM authentication checks if not properly configured.

When a forwarded message is sent, the new forwarding mail server effectively becomes the “sender.” Because this server is not typically authorized in the original sender’s SPF record, SPF checks may fail at the recipient’s end, even though the message is legitimate.

How Auto-Forwarding Works

Auto-forwarding can occur through several methods:

• User-defined rules: Set up within an email client or webmail interface to forward all or specific messages
• Server-side forwarding: Managed by the mail administrator or system policies
• Alias-based forwarding: Configured in DNS or mail routing to send copies to another address

When a message is forwarded, it may retain its original “From” header but use the forwarding server’s IP for delivery. This mismatch often breaks SPF alignment. However, DKIM signatures can survive forwarding since they validate message integrity rather than delivery source.

Challenges of Auto-Forwarding with DMARC

Forwarding introduces several issues for domain authentication:

• SPF alignment fails because the forwarder’s IP is not in the sender’s SPF record
• DKIM signatures can fail if the forwarder modifies message content or headers
• DMARC alignment may fail if neither SPF nor DKIM validation passes

To mitigate these problems, some mail services support ARC (Authenticated Received Chain), which preserves original authentication results during forwarding, allowing recipients to trust the original sender.

Auto-Forwarding and DMARCeye

DMARCeye helps detect and interpret auto-forwarding behavior across your mail ecosystem. By analyzing DMARC reports, the platform identifies patterns of SPF or DKIM failure that occur due to legitimate forwarding rather than malicious activity.

With detailed reporting and policy insights, DMARCeye enables organizations to distinguish between valid forwarding and suspicious rerouting, ensuring accurate enforcement without disrupting legitimate mail delivery.

Sign up for a free trial of DMARCeye today and secure your email domain.

To learn more about DMARC and DMARC-related terms, explore the DMARCeye Glossary.