Summary
Several major ISPs offer domain-based Feedback Loops (FBLs) that utilize DKIM for senders who properly authenticate their mail. The key ISPs that offer FBLs based on DKIM are Gmail, Yahoo, and AOL. While iCloud does not offer a FBL, senders can use Validity's Universal Feedback Loop, which consolidates data from multiple ISPs. Microsoft utilizes IP-based FBL, but provides SNDS to monitor IP reputation, which indirectly impacts domain performance. DKIM is fundamental for establishing these feedback loops and is required by most major ISPs to provide feedback loops, allowing senders to understand if their users are marking the email as spam. Whitelisting, which involves listing your email or IP address as a safe sender, can assist with deliverability in corporate environments. Resources like ReturnPath offer tools to use DKIM-based feedback loops to gain complaint data directly from ISPs. Monitoring tools, such as Spam Resource, also offer insights into senders' reputations, domains, and ISPs.
Key findings
- Gmail, Yahoo, and AOL: Gmail, Yahoo, and AOL are all major ISPs that support DKIM-based FBLs.
- Validity's Universal FBL: Validity provides a universal FBL account that consolidates data from multiple ISPs that support DKIM-based FBLs.
- Importance of DKIM: DKIM is required for most major ISPs to provide FBLs, allowing the sender to understand if their users are marking the email as spam.
- Microsoft SNDS: Microsoft uses IP-based FBL, but provides SNDS to monitor IP reputation, which indirectly impacts domain performance.
- iCloud Lacks FBL: iCloud does not offer a FBL.
Key considerations
- Implement DKIM: Implement DKIM authentication to qualify for feedback loops offered by ISPs and improve sender reputation.
- Register for FBL Programs: Register for feedback loop programs with supporting ISPs to receive reports on spam complaints.
- Use Validity: Consider using Validity's Universal Feedback Loop to consolidate data from multiple ISPs for a comprehensive view of sender reputation.
- Monitor Microsoft SNDS: Monitor Microsoft's SNDS to manage IP reputation and identify potential deliverability issues.
- Whitelisting: Consider Whitelisting your email or IP to ensure recipients receive your emails, particularly in corporate environments.
- Feedback Loop Analysis: Analyze feedback loop data to identify and address spam issues, improving overall deliverability.
What email marketers say
10 marketer opinions
Several ISPs offer domain-based Feedback Loops (FBLs) that utilize DKIM (DomainKeys Identified Mail) to provide senders with data on spam complaints. These FBLs enable senders to monitor their sender reputation, identify deliverability issues, and address problems promptly. Key ISPs mentioned include Gmail, Yahoo, AOL, and Microsoft (indirectly through IP reputation monitoring). Validity's Universal Feedback Loop is also highlighted as a tool to consolidate data from various ISPs, providing a comprehensive view of sender reputation.
Key opinions
- Gmail: Gmail provides DKIM-based FBLs, enabling senders to receive reports when recipients mark their emails as spam.
- Yahoo: Yahoo offers domain-based feedback loops using DKIM, allowing senders to receive reports about spam complaints related to their domains.
- AOL: AOL provides a DKIM-based FBL where senders can track the email addresses that reported spam.
- Validity: Validity's Universal Feedback Loop consolidates data from multiple ISPs, providing a comprehensive view of sender reputation.
- SparkPost: Some ISPs such as AOL and Yahoo, offer domain-based feedback loops (FBLs) using DKIM.
Key considerations
- DKIM Authentication: Ensure emails are authenticated with DKIM, as this is a prerequisite for participating in most domain-based FBLs.
- FBL Setup: Set up FBLs with major ISPs like Gmail, Yahoo, and AOL to monitor spam complaints and improve deliverability.
- Reputation Monitoring: Regularly monitor FBL data to identify and address potential issues with email campaigns, improving overall sender reputation.
- Validity's Universal FBL: Consider using Validity's Universal Feedback Loop to consolidate data from multiple ISPs for a comprehensive view of sender reputation.
- Microsoft SNDS: Monitor Microsoft's Sender Network Data Services (SNDS) to track IP reputation, as it indirectly impacts domain performance and deliverability.
Marketer view
Email marketer from Litmus shares a guide on setting up and monitoring feedback loops, emphasizing the importance of authenticating emails with DKIM. Several ISPs like Gmail and Yahoo offer FBLs based on DKIM, providing data on spam complaints to improve sender reputation.
6 Apr 2022 - Litmus
Marketer view
Email marketer from Stack Overflow shares that setting up a DKIM-based Feedback Loop with major ISPs like Gmail, Yahoo, and AOL is crucial for monitoring spam complaints. By analyzing the FBL data, senders can quickly identify and address potential issues with their email campaigns, improving overall deliverability.
18 Apr 2025 - Stack Overflow
What the experts say
5 expert opinions
Experts provide varied insights regarding Feedback Loops (FBLs) and email deliverability. Some key points include the absence of a FBL from iCloud, the utility of Validity's FBL knowledgebase for managing FBL sign-ups, the importance of feedback loop reporting for understanding sending reputation, the role of whitelisting in ensuring email delivery, and the value of Microsoft's Smart Network Data Services (SNDS) for monitoring IP reputation and identifying deliverability issues. While some ISPs offer DKIM-based FBLs directly, Validity acts as a consolidator of FBL data, and resources like SNDS provide related metrics to enhance deliverability.
Key opinions
- iCloud's Lack of FBL: iCloud does not offer a direct Feedback Loop (FBL).
- Validity's FBL Knowledgebase: Validity's FBL knowledgebase is useful for understanding and managing FBL sign-ups across different companies.
- Feedback Loop Reporting Value: Feedback loop reporting offers insights into sending reputation and identifies spam issues across domains and ISPs.
- Microsoft SNDS: Microsoft's SNDS provides data on spam complaints, spam trap hits, and authentication status, aiding in monitoring IP reputation.
Key considerations
- Validity FBL Knowledgebase: Leverage the Validity FBL knowledgebase for assistance with FBL setup and management.
- Whitelisting: Consider whitelisting practices to ensure email delivery, particularly in corporate environments.
- Microsoft SNDS Registration: Register with Microsoft's SNDS to monitor IP reputation and identify potential delivery issues.
- Monitor Reporting: Implement a process to review your feedback loop reports to better your sending reputation and delivery rates.
Expert view
Expert from Spam Resource explains that feedback loop reporting provides valuable insights into your sending reputation, identifies if your messages are being marked as spam and what domains and ISPs are marking your mail negatively.
17 Sep 2024 - Spam Resource
Expert view
Expert from Spam Resource explains the importance of whitelisting to ensure recipients receive your emails, particularly in corporate environments, and highlights the different levels of whitelisting, including domain whitelisting, DKIM whitelisting, and IP address whitelisting, while noting that some ISPs may require additional information to facilitate whitelisting.
8 Feb 2025 - Spam Resource
What the documentation says
6 technical articles
Several major ISPs, including Gmail and Yahoo, provide feedback loops (FBLs) for senders who authenticate their mail using DKIM. These FBLs offer reports on spam complaints, enabling senders to identify and address deliverability issues. While Microsoft primarily uses IP-based FBLs, their SNDS service helps monitor IP reputation, indirectly impacting domain performance. DKIM is a fundamental requirement for establishing these feedback loops, allowing ISPs to reliably identify senders. Validity (formerly ReturnPath) also highlights the use of DKIM for direct complaint data from ISPs, emphasizing the need for authentication and registration for FBL programs.
Key findings
- Gmail FBL: Gmail provides a DKIM-based feedback loop, offering aggregate reports on spam complaints.
- Yahoo FBL: Yahoo offers spam complaint reports based on DKIM authentication, allowing senders to track email IDs reporting spam.
- Microsoft SNDS: Microsoft uses IP-based FBL but provides SNDS to monitor IP reputation, which indirectly impacts domain performance.
- DKIM Requirement: DKIM is essential for establishing feedback loops and allowing ISPs to identify senders reliably.
Key considerations
- DKIM Implementation: Ensure proper DKIM authentication to qualify for feedback loops offered by ISPs.
- FBL Registration: Register for FBL programs with supporting ISPs to receive spam complaint reports.
- SNDS Monitoring: Monitor Microsoft's SNDS to manage IP reputation and identify potential deliverability issues.
- Feedback Loop Analysis: Analyze feedback loop data regularly to identify and address spam issues, improving overall deliverability.
Technical article
Documentation from RFC explains the technical specifications for DKIM and related authentication methods. DKIM is fundamental for establishing feedback loops, as it allows ISPs to reliably identify the sender of an email, facilitating the delivery of FBL reports.
18 Jan 2025 - RFC
Technical article
Documentation from Yahoo shares information on using DomainKeys Identified Mail (DKIM) to authenticate your messages, as this is the basis for them to supply reports on spam complaints. It allows senders to track the email IDs who reported to spam.
10 Dec 2024 - Yahoo
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