Is the Invaluement blacklist still relevant for email deliverability?

Key findings

• Continued Usage: Several major mailbox providers and security gateways, including BT Internet, FireEye, Mimecast, and Barracuda, utilize Invaluement for email filtering. This suggests a persistent reliance on its data for spam detection.
• Dual Impact: Invaluement can lead to emails being rejected at the gateway for severe listings, or (more subtly) being accepted but filtered directly to recipients' spam folders. The latter can be harder to detect through standard ESP delivery metrics.
• Types of Lists: Invaluement operates different lists, such as ivmURI (domain-based), ivmSIP (IP-based), and ivmSIP/24 (network-based), targeting various aspects of suspicious sending behavior.
• Underreported Impact: The perceived lack of impact in some cases may stem from a misunderstanding of how email blocklists affect inbox placement. Many ESP reports only show delivered status, without distinguishing between inbox and spam folder delivery.

Key considerations

• Monitor Proactively: Even if your current metrics don't show a severe drop, consistent monitoring of your IP and domain against blocklists like Invaluement is crucial for maintaining good sender reputation.
• Beyond Delivery Rates: Look beyond simple delivery success rates and investigate inbox placement, especially if you notice engagement dips or anecdotal reports of emails going to spam.
• Removal Process: Understand the process for requesting removal if your sending infrastructure is listed, as proactive removal can prevent future issues. This is especially true when dealing with shared IP addresses.
• Comprehensive Strategy: Invaluement is one piece of the puzzle. A holistic approach to email deliverability involves managing sender reputation, content, authentication (SPF, DKIM, DMARC), and list hygiene.

Key opinions

• Limited Visibility: Some marketers find it challenging to assess the impact of Invaluement based solely on ESP logs, as these logs often report success even if the email lands in the spam folder.
• Past Experience: Observations from marketers indicate that while Invaluement may have caused direct rejections by certain ISPs in the past (e.g., BT Internet as of 2017), its current impact might be more nuanced, leading to spam folder placement rather than hard bounces.
• Prioritization Challenges: Marketers may deprioritize addressing an Invaluement listing if their internal metrics show good deliverability, overlooking the potential for reduced inbox placement.

Key considerations

• Understand ESP Reporting: Be aware that an ESP's delivered status often only means the mail was accepted, not necessarily that it reached the inbox. True inbox placement requires more advanced monitoring.
• Beyond the Surface: Relying solely on high delivery rates from your ESP can give a false sense of security regarding email deliverability. Consider the impact on engagement metrics like open rates and click-through rates as indicators of spam folder placement.
• Impact on Reputation: Even if Invaluement doesn't cause outright rejection for all recipients, a listing can still contribute to a degraded sender reputation with other providers.
• Address all Blocklists: It's best practice to address all active blocklist listings, regardless of perceived immediate impact, to maintain optimal email performance. You can review a comprehensive list of email blacklists here.

Key opinions

• Persistent Relevance: Invaluement should not be ignored. Many mail providers actively use it for filtering, whether it's for outright rejection at the gateway or for routing emails to the spam folder.
• Widespread Adoption: Beyond BT Internet, a diverse group of providers, including Barracuda, Mimecast, and various regional ISPs, rely on Invaluement's data to inform their filtering decisions.
• Hidden Impact: The primary challenge in assessing Invaluement's impact is that most ESPs do not distinguish between delivery to the inbox and delivery to the spam folder. A success message in logs may still mean the email landed in spam.
• Gateway vs. Spam Folder: Some providers use Invaluement to reject mail outright at the gateway, while others, like Cox, use it as a factor for determining if mail should be placed in the spam folder without rejection.

Key considerations

• Holistic Monitoring: To truly understand deliverability, go beyond basic ESP reports. Implement solutions that monitor blacklist status and provide insights into actual inbox placement, not just delivery success.
• Proactive Management: If listed, initiate the removal process promptly. Ignoring a listing on a blocklist like Invaluement, even if its impact isn't immediately obvious, can lead to broader deliverability issues down the line.
• Understand Blacklist Types: Differentiate between IP-based (ivmSIP), domain-based (ivmURI), and network-based (ivmSIP/24) listings. Each type requires a slightly different approach to remediation and impacts deliverability in distinct ways. More information about the types of email blocklists can be found in our guides.
• Reputation is Key: Maintaining a clean sending reputation is paramount. A listing on Invaluement, regardless of direct bounces, indicates a negative signal that can affect your overall sender score with ISPs and lead to suppressed deliverability for critical email streams.

Key findings

• Composition: Invaluement comprises multiple commercial anti-spam blacklists, primarily ivmURI (for domains owned by spammers), ivmSIP (for spammy IP addresses), and ivmSIP/24 (for spammy network blocks). These distinctions are important for targeted remediation.
• Purpose: The service is designed to detect and list senders who attempt to circumvent traditional spam detection methods, indicating its role in identifying more persistent or sophisticated spamming behaviors.
• Stated Impact: Documentation from sources like Return Path states that Invaluement listings can have a high impact on email deliverability, often leading to rejections at the gateway.
• Usage by ISPs: Many email service providers integrate Invaluement's lists into their filtering systems to enhance spam detection and improve email filtering accuracy.

Key considerations

• Understand Listing Criteria: Familiarize yourself with what triggers a listing on Invaluement (e.g., sending to spam traps, high complaint rates, or suspicious sending patterns) to avoid future listings. You can read more about how email addresses end up on blacklists for more details.
• Removal Guidelines: Consult Invaluement's own removal instructions (e.g., for ivmSIP listings) to ensure you follow the correct procedures for delisting your IP or domain. The RackAid blog offers relevant guidance.
• Comprehensive Strategy: Adhere to industry best practices for email sending, including maintaining clean lists, sending relevant content, and ensuring proper authentication (SPF, DKIM, DMARC), to minimize the risk of being listed on Invaluement or any other blocklist.