Why is my domain listed in Razor2 and how do I remove it?
Matthew Whittaker
Co-founder & CTO, Suped
Published 10 Jul 2025
Updated 10 Oct 2025
7 min read
Finding your domain listed on any blacklist (or blocklist) can be alarming, especially when you are unsure why or how to remove it. Razor2, a component often used by SpamAssassin, operates differently from typical IP-based or domain-based blacklists, making its listings particularly perplexing. Unlike many DNSBLs, Razor2 focuses on the content of your emails rather than the sender's IP address or domain directly.
If you've received reports indicating that your emails are being penalized by Razor2, it means that the system has identified patterns in your message content that are highly similar to previously reported spam. This guide will clarify how Razor2 functions, common reasons for a listing, and practical steps to address and prevent future issues related to email deliverability.
Understanding Razor2 and how it works
Razor2 is a distributed, collaborative spam detection system. It works by generating fuzzy checksums (or signatures) of email body content. When an email passes through a system using Razor2, its content is hashed, and this hash is checked against a database of known spam signatures. If there's a match, the email is flagged as spam.
This means your domain isn't listed in the traditional sense, but rather your email content is triggering a match with known spam patterns. Even if your domain's sender reputation is generally good, a Razor2 flag can still lead to messages landing in the spam folder.
The key distinction is that Razor2 doesn't block by IP or domain but by the fingerprint of the message body. This makes it a powerful tool for catching evolving spam campaigns that might quickly switch sender IPs or domains. Understanding this mechanism is the first step toward diagnosing and solving any issues.
Common reasons for a Razor2 listing
There are several reasons your domain might encounter a Razor2 listing, even if you believe you haven't sent bulk email recently. The system is designed to detect similarities in content, which can sometimes be triggered unexpectedly.
Compromised account: One of the most common causes is an unauthorized party (a spammer) using your domain or an associated sending system. This can happen if an email account or an application configured to send emails with your domain is compromised, leading to spam being sent without your knowledge.
Content similarity: Your legitimate email content might inadvertently resemble spam patterns that Razor2 has previously identified. This could be due to specific phrases, links, image structures, or even HTML formatting commonly found in spam.
Past sending activity: If your domain was used for sending spam in the past, even if it was a while ago, the content hashes might still exist within the Razor2 network. When you start sending again, these old patterns could trigger a listing.
To pinpoint the source, you need visibility into your email sending activity. This is where DMARC reports become invaluable. They provide aggregated data on who is sending email using your domain, whether they pass authentication (SPF and DKIM), and what actions recipients take on those emails.
Utilizing a DMARC monitoring tool like Suped can help you identify if unauthorized servers or applications are sending email on your behalf. These reports often reveal sending sources you might have forgotten about or never knew existed, which could be the origin of the problematic content.
The challenge of delisting from Razor2
Unlike other email blocklists where you can submit a delisting request for an IP or domain, directly removing your domain from Razor2 is generally not possible. As cPanel Support explains, Razor2 is not a normal blacklist (RBL/DNSBL) that takes delisting requests.
Since Razor2 works on content signatures, the solution lies in changing the content that is triggering the spam flag and ceasing any practices that contribute to your domain being seen as a source of spam. If unauthorized sending is occurring, simply stopping the sending from the compromised source is crucial.
Traditional blacklists
Often IP-based or domain-based. Block email based on the sender's IP address or domain reputation.
Delisting process: Typically involves submitting a delisting request to the blocklist operator after resolving the underlying issue. For example, removing your IP from Spamhaus involves specific steps.
Focus: Sender identity and sending behavior.
Razor2
A content-based filtering system. Flags emails if their body content matches known spam signatures.
The distributed nature of Razor2 means that fixing a listing isn't about contacting a single entity. It's about modifying your email practices so that your content no longer matches the signatures of spam recognized across its network of clients.
For specific services like Keap, there might be internal processes to request delisting, but these are typically for the IPs they use, not direct Razor2 delisting. Your focus should remain on addressing the root cause, which is often related to content or unauthorized sending.
Preventing future Razor2 listings
Preventing future Razor2 listings requires a proactive approach to your email security and content strategy. Here are the steps you can take:
Identify and stop unauthorized sending: Review your DMARC reports to see all sources sending mail on behalf of your domain. If you find unknown or unexpected senders, investigate immediately and take steps to secure or shut down those channels. Suped's DMARC monitoring can provide the visibility you need.
Review email content: If the issue isn't unauthorized sending, scrutinize your email content. Look for common spam triggers, excessive links, suspicious formatting, or phrases often associated with promotional or unsolicited mail. Consider using an email deliverability tester to pre-check your messages.
Implement strong email authentication: Ensure your domain has correctly configured SPF, DKIM, and DMARC records. This helps protect your domain from spoofing and builds trust with receiving mail servers.
Regularly monitor your domain's sending reputation and ensure all your legitimate sending sources are authorized and properly authenticated. Staying vigilant is key to maintaining good email deliverability.
Views from the trenches
Best practices
Actively monitor DMARC reports to detect any unauthorized sending from your domain, which can trigger Razor2 flags.
Regularly review your email content for elements that might be perceived as spammy, such as excessive links, certain keywords, or poor formatting.
Implement robust email authentication protocols (SPF, DKIM, DMARC) to prevent spoofing and unauthorized use of your domain.
If using an email service provider, ensure their sending practices align with anti-spam guidelines to maintain a good sender reputation.
Common pitfalls
Mistaking Razor2 for a traditional RBL and attempting direct delisting, which is usually not possible or effective.
Assuming a lack of recent bulk email means no sending activity, neglecting older compromised systems or forgotten applications.
Failing to understand that Razor2 filters based on content checksums, not just sender reputation or IP address.
Overlooking subtle changes in email templates or campaign messaging that might introduce spam-like characteristics.
Expert tips
Razor2 is content-based, so focusing on optimizing email content for deliverability is more effective than IP/domain delisting.
Use DMARC reports to find all sending sources. If a server is compromised, it could be sending spam content.
The solution to a Razor2 listing is to stop using content that looks like spam and address any practices causing your domain to be considered a spammer.
Poor domain reputation with other filters like Proofpoint can correlate with Razor2 issues, indicating a broader deliverability problem.
Marketer view
A marketer from Email Geeks says that a domain listed on Razor2 might have been recently used, and they should check their DMARC monitoring for any indicators.
March 17, 2020 - Email Geeks
Marketer view
A marketer from Email Geeks suggests that Razor2 uses content matching, flagging domains seen sending content similar to known spam. The listing's timing likely indicates recent sending activity.
March 17, 2020 - Email Geeks
Moving forward with confidence
Being listed in Razor2 is a strong indicator that your email content or sending practices are being perceived as spam. Since direct delisting is not an option, your efforts must focus on internal remediation. This involves diligent DMARC monitoring and content optimization.
By understanding Razor2's content-based filtering and taking corrective action to secure your sending infrastructure and refine your message content, you can improve your email deliverability and avoid future blocklist issues.
