Why is a reputable sender getting informational listings or active listings at Spamhaus?
Michael Ko
Co-founder & CEO, Suped
Published 17 May 2025
Updated 16 Aug 2025
7 min read
It can be perplexing and frustrating when a sender with a solid reputation suddenly finds their IP address or domain listed on Spamhaus, whether it's an informational alert or an active blocklist. You follow all the best practices, maintain clean lists, and your engagement rates are strong, yet an unexpected listing appears. This often leads to questions about what went wrong and how to fix it.
Informational listings, in particular, can be confusing because they don't always immediately disrupt email delivery. Unlike active blocklists that directly result in bounced emails or messages diverted to spam folders, informational listings are more like a yellow flag. They signal that something is amiss, but the full impact might not be felt right away.
However, even for highly reputable senders, these listings are not arbitrary. They are typically triggered by specific patterns or events that Spamhaus's systems detect. Understanding these underlying causes is crucial for prevention and effective resolution, ensuring your valuable emails continue to reach the inbox.
Spamhaus is one of the most widely used and influential blocklist (or blacklist) authorities in the email ecosystem. Their various lists, such as the Spamhaus Blocklist (SBL), Exploits Blocklist (XBL), Domain Blocklist (DBL), and Combined Spam Sources (CSS), are designed to identify and list IP addresses and domains associated with various forms of unsolicited or malicious email activity. Internet service providers (ISPs) and mail servers around the globe rely on these lists to filter out unwanted traffic, which directly impacts your email deliverability. For a deeper dive into how these lists function, you can review how email blacklists work.
Informational listings (advisory)
These are early warnings, indicating that an IP or domain is exhibiting suspicious behavior but might not yet be causing direct harm. They are advisory and typically do not result in immediate email blocks by ISPs. However, they are a clear signal that something needs attention. Spamhaus views them as a crucial step before more severe actions are taken. You can find more details on this topic from Spamhaus directly regarding informational listings.
Active listings (hard blocklists)
When an IP or domain is placed on an active blocklist, it means Spamhaus has identified clear evidence of spamming or malicious activity. These listings often lead to significant deliverability issues, including emails being bounced, rejected, or routed directly to spam folders. They require immediate investigation and action to facilitate delisting and restore sending reputation.
The key distinction is the immediacy of impact. An active listing (or blacklist) directly interferes with your email flow, whereas an informational listing (or blocklist) serves as a pre-warning. Reputable senders are typically concerned with informational listings because they indicate a deviation from expected email behavior, even if not yet classified as blatant spam. This can still lead to a decline in domain reputation over time.
Common triggers for seemingly reputable senders
One of the most common reasons for a reputable sender to receive a Spamhaus listing, especially an informational one, is hitting spam traps. Spam traps are email addresses used by anti-spam organizations, like Spamhaus, to identify senders of unsolicited bulk email. These addresses are not used for legitimate correspondence and should never appear on a valid mailing list. Even a small number of hits, particularly to pristine or virgin spam traps, can trigger an alert, as it indicates poor list acquisition practices or outdated contact lists. For more information on this, see how spam trap hits trigger listings.
Beyond spam traps, poor sending practices can also lead to listings. This includes sending to dormant or unengaged segments of your list, even if they were originally opted-in. If emails are repeatedly sent to recipients who never open, click, or interact with your messages, it can signal to Spamhaus that your list hygiene isn't as robust as it should be. While this isn't outright spamming, it's inefficient and can contribute to a negative sender reputation.
Another factor could be an unintentional resemblance to snowshoe spam patterns. Snowshoe spam involves distributing low volumes of spam across a large number of IP addresses to evade detection. Even if your sending is legitimate, if your infrastructure setup (e.g., using multiple IPs in a round-robin fashion, especially with Virtual Private Servers or shared IPs) somehow mirrors these patterns, it could trigger an informational listing. This isn't about you being a snowshoe spammer, but rather your sending characteristics overlapping with patterns they look for, particularly in lists like the Combined Spam Sources (CSS).
The warning signs of informational listings
While an informational listing might not immediately block your emails, it's a critical signal you shouldn't ignore. Think of it as a warning light on your car's dashboard: it doesn't mean your engine has seized, but it indicates a problem that, if left unaddressed, could lead to a breakdown. ISPs and mail administrators often subscribe to Spamhaus's various blocklists and datasets, including those that contain informational listings.
Ignoring these warnings can have a cascading effect. Spamhaus states that if initial signals and informational listings are overlooked, the sending IP will likely graduate to an active listing (or blacklist). This transition will directly impact your email deliverability, leading to bounces, rejections, and increased spam folder placement. It's effectively Spamhaus's way of giving senders a chance to self-correct before more severe measures are implemented.
Even before a full blocklist occurs, informational listings can subtly erode your sender reputation. ISPs may interpret these warnings as a sign of diminishing trust, which can influence their internal filtering decisions. This might manifest as more of your emails landing in the spam folder rather than the inbox, even for highly engaged recipients. This impact can be challenging to detect without granular deliverability insights, making proactive monitoring essential.
Proactive measures and resolution for listings
The best defense against any Spamhaus listing is a strong offense, meaning proactive email list management and consistent monitoring. Regularly clean your email lists to remove inactive, invalid, or suspicious addresses. Implement a stringent double opt-in process for all new subscribers to ensure explicit consent and reduce the risk of spam trap hits. Also, focus on sending only to engaged subscribers who actively interact with your emails.
Monitor regularly: Utilize blocklist monitoring tools to stay informed about your IP and domain status across various blacklists, including Spamhaus. This allows for immediate action upon detection of any listing.
Segment lists: Segment your audience based on engagement. Consider suppressing or re-engaging subscribers who haven't opened or clicked in a significant period to reduce the risk of sending to dormant or invalid addresses that could become spam traps.
Authenticate email: Ensure your SPF, DKIM, and DMARC records are correctly configured and aligned. This helps ISPs verify your legitimacy and can prevent listings associated with spoofing or unauthorized sending.
If you receive an informational or active listing, investigate immediately. Spamhaus often provides a reason for the listing via their Blocklist Removal Center. Use this information to pinpoint the exact issue. If it’s a spam trap hit, identify how the address got onto your list. If it's related to sending patterns, analyze your recent campaigns. Then, follow their delisting process, which typically requires addressing the root cause before removal is granted.
Protecting your sender reputation
Receiving a Spamhaus listing, whether informational or active, is a clear indication that your email sending practices require attention. Even for reputable senders, subtle shifts in list hygiene, engagement patterns, or infrastructure setup can trigger these warnings. Proactive monitoring, rigorous list management, and a quick response to any alerts are essential to maintain your sender reputation and ensure your emails consistently reach their intended recipients.
Views from the trenches
Best practices
Act quickly on informational listings; they are strong indicators of potential issues and precursors to active blocklists.
Implement a double opt-in process for all new subscribers to ensure explicit consent and reduce spam trap hits.
Regularly clean your email lists by removing unengaged or invalid addresses to improve list hygiene and sender reputation.
Segment your email sends based on recipient engagement to avoid sending to dormant contacts that could become problems.
Common pitfalls
Ignoring informational listings, assuming they don't affect deliverability, which often leads to future active listings.
Failing to implement a robust double opt-in, leading to spam trap hits and complaints.
Sending to outdated or unengaged email lists, which increases the risk of hitting spam traps.
Not monitoring your IP and domain regularly for blocklist status across various providers like Spamhaus.
Expert tips
Ensure your email authentication (SPF, DKIM, DMARC) is correctly configured and aligned to verify your sending legitimacy.
Analyze bounce logs regularly to identify persistent issues with invalid addresses and proactively remove them.
Understand how your ESP manages IP reputation, especially if using shared IP addresses, as their practices affect your standing.
If using dedicated IPs with round-robin, ensure each IP maintains a strong individual reputation through balanced sending.
Marketer view
A marketer from Email Geeks says they observed an uptick in Spamhaus informational listings, with stricter thresholds implemented since early July.
2022-07-13 - Email Geeks
Expert view
An expert from Email Geeks says that the informational listings are legitimate, indicating customers are hitting Spamhaus spam traps, and these listings are expected to reappear.
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