technical · sourced answer
Abuse Reporting Format (ARF) Explained
The Abuse Reporting Format (ARF) is a standardized format for feedback reports sent by mailbox providers to email senders. Defined in RFC 5965, it allows providers to notify senders when a recipient marks a message as spam or abuse, enabling the sender to remove that address from their mailing lists.
Technical Definition
ARF is a structured reporting mechanism that provides a consistent way for receiving mail servers to communicate user complaints back to the originating sender. It replaces fragmented, provider specific feedback loops with a uniform standard. The report typically includes a feedback report header and a portion of the original message to help the sender identify the specific campaign or user that triggered the complaint.
Mechanical Operation
When a user clicks Mark as Spam, the receiving server generates an ARF report. This report is sent to the address specified in the ARF header or the DMARC report address. The message contains a Feedback-Report header with a version number and a type, such as abuse or spam. The body of the report contains the original message headers and a snippet of the content, allowing the sender to map the complaint to a specific internal record.
Importance for Senders
Processing ARF reports is critical for maintaining sender reputation. Ignoring these reports leads to higher complaint rates, which signals to mailbox providers that the sender is transmitting unwanted content. By automating the processing of ARF reports, senders can immediately unsubscribe complaining users, reducing the risk of being blacklisted or having messages routed directly to the spam folder.
Operational Notes
A common mistake is failing to configure a dedicated mailbox or webhook to ingest these reports. Because ARF reports arrive as emails, they can be lost in general support queues. Senders should use tools like SendHQ free tools (https://sendhq.cc/tools) to verify their DNS and authentication settings to ensure reports are routed correctly. Another error is failing to parse the original message ID from the ARF body, making it impossible to identify the offending email.
Example Structure
A typical ARF report contains a header like Feedback-Report: version=1.0; type=abuse. The body includes the original message headers, such as the From, To, and Subject lines, followed by the original message content. This structure allows the sender to see exactly which email caused the user to complain, including the timestamp and the specific recipient address.
Questions teams ask
Is ARF the same as DMARC reporting?
No. DMARC reports focus on authentication failure and alignment, while ARF reports focus on user behavior, specifically when a user marks a message as spam.
Do all mailbox providers support ARF?
Most major providers support ARF or a variation of it, though some may require you to register for a Feedback Loop (FBL) to receive them.
How should I handle an ARF report?
You should automatically parse the report, extract the recipient email address, and immediately remove that address from all active mailing lists.
Primary sources
- RFC 5965: An Extensible Format for Email Feedback Reports — RFC Editor
- M3AAWG Best Common Practices — M3AAWG