Summary
When your SenderScore report shows millions of emails sent from your dedicated IP address that you cannot account for, it signals a significant underlying issue. While initial thoughts might lean towards shared IP addresses or data reporting errors, the consensus among experts and marketers points to potential account compromise or specific technical configurations that inflate reported volumes.
Key findings
- Dedicated IP vs. Shared IP: One of the first considerations for unexpected volume is whether the IP is truly dedicated or if it's a shared IP address. Misinformation from ESPs can lead to this confusion, requiring thorough verification.
- Account Compromise: If the volume spikes are confirmed by multiple reporting platforms, a common cause is an account breach where malicious third parties are using your credentials or API keys to send spam.
- Data Accuracy and Alignment: SenderScore's reports are generally reliable, especially when aligned with trends seen on other reputation tools like Talos Intelligence. Discrepancies between reported volume and your internal sending logs suggest a potential external issue.
- Aggressive Retries: Soft bounces, combined with an ESP's aggressive retry mechanism, can be counted as additional volume by mailbox providers feeding data to SenderScore, leading to inflated numbers.
Key considerations
- Verify IP Type: Double-check with your ESP to confirm you are indeed on a dedicated IP address, if that's what you expect. Sometimes, what's believed to be dedicated is actually shared.
- Internal Log Review: Thoroughly review your own email sending logs (MTA activity) to compare with SenderScore's reported volume. This is crucial for identifying unauthorized sends.
- Security Audit: If unauthorized sending is suspected, immediately initiate a security audit. This includes revoking API keys, resetting passwords, and checking for any compromised credentials.
- Understand Reporting Mechanics: Be aware that various factors, such as how SenderScore collects data (e.g., counting retries), can influence reported volumes. For more details on this, consult the official Sender Score website.
What email marketers say
Email marketers grappling with inexplicable email volumes on SenderScore often first question their setup and ESP's information. Many are quick to check if they're on a shared IP, or if the reporting tool itself is inaccurate. The general sentiment points to a frustrating experience, as unaccounted volume can severely impact sender reputation and deliverability.
Key opinions
- Initial Skepticism: Marketers frequently express disbelief when faced with such high, unexplainable volumes, often suspecting a misconfiguration or an ESP's oversight regarding shared versus dedicated IPs.
- Seeking Peer Advice: There's a strong inclination to ask peers for advice on investigation options when faced with perplexing SenderScore reports.
- Volume Discrepancy Concerns: Even when other reputation tools show spikes, the lack of actual volume data can make it hard for marketers to confirm the scale of the issue independently. For more on this, check Mailjet's guide on sender score.
- Impact on Reputation: Marketers recognize that such high, unexplained volumes can significantly damage their sender reputation and potentially lead to blacklisting (or blocklisting).
Key considerations
- ESPs as First Point of Contact: Always engage your ESP first for clarification on IP allocation and their internal sending logs. They should be able to provide data on MTA activity.
- Confirming IP Status: Do not assume your IP is dedicated; actively confirm it multiple times if there's any doubt.
- Monitoring Reputation Tools: While SenderScore is a primary indicator, cross-referencing with other reputation tools is vital to confirm trends, even if specific volume numbers aren't provided. This proactive approach can help troubleshoot a dropping sender score.
- Security Vigilance: If internal checks don't explain the volume, marketers should prepare for a potential security incident and take immediate steps to secure their sending infrastructure.
Marketer view
Email marketer from Email Geeks asked for help investigating unaccounted millions of emails from their IP on SenderScore. They expressed confusion as their DMARC was set up and SenderScore had found nothing suspicious, suggesting a forwarding issue which seemed unlikely given the sheer volume.
Marketer view
Email marketer from Email Geeks inquired if the user was on a shared IP address, as this is a common reason for unexpected email volume. They suggested this as a first, obvious step in troubleshooting the issue.
What the experts say
Experts universally dismiss the idea of email forwarding accounting for millions of unexpected emails. Instead, their focus immediately shifts to potential security compromises or very specific technical scenarios. They emphasize the critical role of accurate logging and immediate response measures to mitigate damage to sender reputation.
Key opinions
- DMARC Irrelevance to IP: Experts clarify that DMARC authentication is not directly tied to the sending IP address. Therefore, its proper setup would not prevent an IP-level volume discrepancy due to unauthorized sending from that IP.
- Account Compromise is Key: The primary suspect for massive, unaccounted email volume is a compromise where a malicious third party has gained access to sending credentials or an account.
- Backend Calculation Errors: While less common for such large discrepancies, experts acknowledge that backend volume calculation errors by the reporting service (like SenderScore) could be a factor.
- Log Analysis is Crucial: Analyzing MTA activity logs from the ESP is paramount to verify reported volumes and identify suspicious sending patterns.
- Treat as Breach: If external reporting aligns with spikes not present in internal logs, the situation should be treated as an account breach requiring immediate security measures. For further reading, see LuxSci's advice on fixing IP reputation.
Key considerations
- Independent Verification: Use multiple reputable tools to cross-reference reported volumes and trends, even if they don't provide exact numbers. This helps confirm the legitimacy of the spikes.
- Immediate Security Action: If a discrepancy persists, prioritize locking down access. This includes revoking all API keys and shutting off access for all users until the source is identified. Refer to our guide on managing senders during a blacklisting.
- Internal Log Deep Dive: Insist on a detailed review of your ESP's mail transfer agent (MTA) logs. These logs provide the authoritative record of emails sent from your IP.
- Proactive Monitoring: Implement robust monitoring for sudden changes in email volume, reputation, and authentication failures to catch issues early.
Expert view
Expert from Email Geeks clarified that DMARC is not fundamentally tied to the IP address, so its correct setup would not mitigate an issue of unaccounted email volume from a specific IP. This points towards other potential root causes.
Expert view
Expert from Email Geeks suggested that a compromise, such as leaked credentials leading to a malicious third party using the account to send spam, is a very plausible explanation for unexpected high volume. They emphasized that this has been observed before.
What the documentation says
Official documentation and technical explanations from reputation services shed light on how they collect and interpret email volume data. A key insight is that the method of counting, particularly concerning retries for soft bounces, can significantly inflate reported numbers. This highlights the need to understand the nuances of how reputation scores are calculated.
Key findings
- Retry Counting: Mailbox providers, who supply data to SenderScore, often count each retry attempt after a soft bounce as a new email send. This can lead to drastically inflated volume reports for heavily deferred mail.
- Data Source Diversity: SenderScore aggregates data from a wide network of mailbox providers. This broad data collection ensures a comprehensive view but also means their metrics might capture activity not directly initiated by the sender's application.
- Volume vs. Reputation: High volume, even from legitimate retries or unauthorized activity, directly impacts the IP's reputation score. Tools like Talos Intelligence provide insight into overall traffic, which can correlate with SenderScore's volume spikes.
- Blacklist Implications: Excessive or unexpected volume, regardless of origin, can quickly lead to an IP being listed on a blacklist (or blocklist), especially if the content is deemed suspicious or spammy. Learn more in our guide, How email blacklists actually work.
Key considerations
- Review ESP Retry Policy: Understand your ESP's retry logic and how it might contribute to inflated volume counts. Adjusting retry aggressiveness could reduce reported volume from soft bounces.
- Monitor Soft Bounces: Keep a close eye on your soft bounce rates. High soft bounce rates followed by aggressive retries can trigger unusual volume reports.
- Consult Validity Knowledge Base: For specific insights into how SenderScore (a Validity product) functions, their knowledge base is an essential resource. They provide detailed explanations of their methodologies.
- Data Correlation: Always try to correlate external reputation data (like SenderScore) with your internal sending logs and DMARC reports to get a complete picture of your email traffic.
Technical article
Validity documentation explains that a potential issue for unusually high reported volume is soft bouncing combined with aggressive retries. They confirm that their Mailbox Provider partners, who supply SenderScore data, often count each retry after a soft bounce as additional volume.
Technical article
SenderScore.org's documentation highlights that the score evaluates IP reputation based on a 30-day moving average of sending behavior, including volume and complaint rates. Any sudden, unexplained surge in volume would therefore immediately impact this score negatively.
Related resources
15 resources
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