How important is IP reputation versus domain reputation, especially for B2B senders with low engagement and emails going to spam?

Key findings

• Domain prioritization: Google, and increasingly other mailbox providers, tend to prioritize domain reputation over IP reputation for deliverability decisions.
• Volume thresholds: Establishing a robust IP reputation may require significant daily sending volume (e.g., 2,000+ emails to Gmail), with lower volumes (e.g., 100-5000 daily) sometimes considered teeny tiny by major providers, making reputation building unpredictable.
• Engagement is key: Recipient engagement (opens, clicks) and overall user behavior are crucial indicators for mailbox providers, particularly for B2B emails, as they reflect whether the mail is truly wanted.
• Shared IP risks: A poor reputation on a shared IP pool can severely impact deliverability, even if your domain itself has good standing, due to the actions of other senders sharing that IP (your neighbors). This underscores the importance of blocklist monitoring.
• Spam folder issue: Very low open rates (e.g., 0.3% at Gmail) are a strong indication that emails are consistently being delivered to the spam folder, signaling a significant sender reputation problem.

Key considerations

• Diagnose the root cause: If emails are going to spam, the core issue is often the domain reputation and the mailstream itself. Focus on improving the perceived value and desiredness of your content.
• Consider private IP carefully: Moving to a private IP is beneficial if a shared IP is the clear issue, but for low-volume B2B senders, establishing a new reputation can be a slow process without sufficient consistent volume.
• Monitor widely: Reputation issues with one major mailbox provider often indicate underlying problems that are affecting deliverability across all mailbox providers, not just specific ones.
• Wholesale program changes: Fixing severe deliverability issues often requires a complete overhaul of email sending practices, including list hygiene, content relevance, and sending frequency, rather than minor adjustments.
• Mailstream reputation: The ultimate goal is to send mail that recipients genuinely want, as this positive user behavior is what fundamentally builds and maintains a strong sender reputation.

Key opinions

• Volume for data: While 100+ emails daily to Gmail are needed for Google Postmaster Tools data, some marketers believe significant volume (2,000+) is required for meaningful IP reputation building.
• Shared IP impact: A shared IP pool with a poor reputation can override a sender's good domain standing, making it difficult to achieve inbox placement.
• B2B filtering: B2B emails encounter diverse enterprise filtering solutions (like Proofpoint or Mimecast) with varying spam classification thresholds.
• Domain vs. IP: Many marketers find Google emphasizes domain reputation and user engagement more than IP reputation, especially for ongoing performance.
• Consistency: Maintaining a consistent sending cadence is seen as a good objective for establishing IP reputation.

Key considerations

• Assessing shared IP issues: Marketers should investigate the reputation of their shared IP neighborhood (e.g., using Cisco's Talos Intelligence) to determine if a dedicated IP is necessary.
• Low open rates: Extremely low open rates (e.g., 0.3%) are a clear sign of significant deliverability issues across multiple mailbox providers.
• Client communication: It can be challenging to convey to clients that current sending practices are problematic and require a fundamental change to improve sender reputation.
• User behavior: Focusing on improving user engagement and recipient behavior is paramount for B2B email success, as it directly influences inbox placement.

Key opinions

• Domain over IP: Experts largely agree that Google places far more emphasis on domain reputation than IP reputation, especially for low-volume senders.
• Mailstream reputation: The overriding factor for deliverability is whether recipients genuinely desire the email content, as this directly influences their engagement and, consequently, sender reputation.
• Volume limitations: Low sending volumes (e.g., 100 messages daily) are considered tiny and can lead to unpredictable reputation behavior with major mailbox providers.
• B2B specifics: B2B email deliverability involves confronting various enterprise filtering solutions, where user engagement and content relevance play a significant role in determining inbox placement.
• Spam folder indication: A very low open rate (e.g., 0.3%) clearly indicates that emails are being filtered directly into the spam folder, signifying a severe reputation issue.

Key considerations

• Focus on desired content: Instead of obsessing over raw IP or domain metrics, prioritize sending content that recipients want, as this is the fundamental driver of positive reputation.
• Address spam placement first: The immediate priority for senders with low open rates should be to implement strategies that move emails from the spam folder to the inbox.
• Holistic program changes: Solving deep-seated deliverability problems requires a comprehensive re-evaluation and overhaul of the entire email program, not just superficial adjustments.
• Understanding filters: Recognize that different mailbox providers and enterprise filters have varying criteria and thresholds for classifying spam.
• Long-term approach: Building a strong sender reputation is a continuous process that reflects historical sending patterns and recipient interactions, requiring patience and persistent effort.

Key findings

• Data requirements: Mailbox providers often specify minimum sending volumes for reputation data to be displayed in their tools, such as the 100+ daily emails required for Google Postmaster Tools.
• Authentication impact: Protocols like SPF, DKIM, and DMARC are foundational for establishing and maintaining both IP and domain reputation by verifying sender identity.
• User engagement signals: Beyond technical authentication, documentation increasingly points to user engagement (opens, clicks, replies, spam complaints) as critical signals influencing inbox placement and overall sender reputation.
• Content relevance: The content and relevance of emails to recipients are vital, as unwanted mail leads to negative engagement signals (e.g., deletions, spam reports), damaging reputation.

Key considerations

• Implement authentication: Properly configuring SPF, DKIM, and DMARC is a fundamental step to validate your sending sources and protect your domain's reputation from spoofing and abuse.
• Monitor feedback loops: Leverage feedback loops and Postmaster Tools to gain insights into how mailbox providers perceive your mail and to identify issues like spam complaints or low engagement.
• Maintain list hygiene: Regularly cleaning email lists to remove inactive users, invalid addresses, and spam traps is crucial for maintaining a healthy sender reputation and avoiding blacklists.
• Adhere to sending guidelines: Comply with sender requirements set by major providers (e.g., Google, Yahoo, Microsoft) to ensure your emails meet their technical and content standards for delivery.