How to fix a Spamhaus CBL listing when using multiple ESPs and Bluehost?

The key to resolving a CBL listing and restoring deliverability lies in a comprehensive approach: identifying and rectifying the root causes of the spamming activity, coordinating technical fixes, and implementing robust best practices across all sending platforms. Simply moving to new infrastructure without addressing the core issues risks being categorized as a "snowshoe" spammer, leading to further, more persistent blocklists. Understanding what causes Spamhaus blacklisting is the first step towards a lasting solution.

Key findings

• Multiple ESPs: Operating email campaigns through three or four different ESPs and an in-house Bluehost solution is a significant red flag, often indicating uncoordinated or problematic sending practices.
• CBL listing: Several IPs are listed on the Spamhaus CBL (Composite Blocking List), leading to emails going to junk.
• Lack of awareness: The client, despite being a legitimate business, lacked awareness of proper email marketing best practices and deliverability issues.
• Past sending issues: Previous attempts with Mailgun, Amazon ECS, and other ESPs also resulted in emails going to spam or mass email sending permissions being denied.
• Bluehost involvement: The CBL listing mentions Microtik routers, and reverse DNS resolves to Bluehost, suggesting a vulnerability on their Bluehost server.

Key considerations

• Avoid 'snowshoe' behavior: Simply migrating to new domains or ESPs without fixing underlying issues can lead to being flagged as a 'snowshoe' spammer, worsening the problem.
• Address root causes: Focus on identifying and fixing the specific practices that led to the Spamhaus listing, such as list acquisition, content, or sending volume. For more details, refer to IPXO's guide on removing IPs from Spamhaus.
• IT team coordination: Bluehost server vulnerabilities, firewall configurations, and port security (e.g., locking down port 25 while using port 587 for authenticated sending) must be addressed by the client's IT team.
• Education and strategy: Educating the client on email marketing best practices and developing a cohesive, singular email sending strategy across fewer, optimized platforms is crucial for long-term success. Understanding an in-depth guide to email blocklists is beneficial.

Key opinions

• Multi-ESP red flag: Using multiple ESPs concurrently is seen as an immediate indicator of potential deliverability problems, suggesting fragmented strategies and a lack of centralized control.
• Snowshoe risk: Marketers frequently warn that changing ESPs or domains simply to escape a blocklist carries the risk of being labeled a snowshoe spammers.
• Root cause analysis: It is crucial to understand and fix the underlying reasons for the listing, rather than just seeking a quick delisting.
• Client education: Many marketers find clients are legitimate but lack fundamental knowledge of email deliverability best practices, requiring significant education.
• Historical sending data: Past sending activities with various providers (Mailgun, Amazon ECS, Bluehost, Ontraport, Infusionsoft) that resulted in spam folder placement indicate a pattern of poor sending. This highlights why your emails are going to spam.

Key considerations

• Stop or warm up: A key question is whether to stop all emailing immediately or to begin warming up a new subdomain with an engaged audience while working on delisting. This decision often depends on the severity and persistence of the block. For guidance on such issues, explore what to do if listed in Spamhaus.
• IP investigation: Specific IPs listed (e.g., 83.221.143.15, 162.241.253.12, 173.236.20.192) need to be identified and their source of abuse pinpointed.
• IT collaboration: Technical issues related to Bluehost servers, such as Microtik routers or reverse DNS, require close collaboration with the client's IT team and Bluehost support. This includes understanding the nature of the hosting (managed VPS vs. self-managed).
• Auditing acquisition process: A thorough audit of the email acquisition process (e.g., opt-ins on landing pages for courses, challenges) is necessary to ensure compliance with best practices.

Key opinions

• Underlying practice issues: Mailing from numerous ESPs suggests fundamental flaws in best practices that technical solutions alone cannot fix.
• Spamhaus unforgiving: Spamhaus will not be lenient if a client is relisted, demanding significant and lasting changes once their attention has been drawn.
• Client transparency: Experts often suspect clients might not be fully transparent about their sending history or the feedback received from their ESPs.
• Batch and blast: A client's adherence to batch and blast sending methods signals potential turbulence and further deliverability issues.
• Technical vulnerabilities: Concerns about technical documents describing a potential botnet or insecure server configurations, particularly relating to Microtik routers and Bluehost IPs, are significant.

Key considerations

• Comprehensive audit: A thorough investigation into the client's email acquisition process and historical sending patterns is essential. This aligns with advice on technical solutions from top performing senders.
• IT collaboration on Bluehost: IT teams must ascertain if the Bluehost server is a managed VPS or self-administered, and how Bluehost can assist in resolving the listing, especially concerning firewall rules and port configurations. Understanding what happens when your IP gets blocklisted is critical.
• Port security: Ensure port 25 is locked down and logging attempts, while port 587 is properly configured for authenticated outgoing mail.
• Client commitment: Assess the client's willingness to make significant, lasting changes to their sending practices, as superficial adjustments will not lead to long-term deliverability.

Key findings

• CBL purpose: The Spamhaus CBL lists IPs actively sending spam or those compromised by malware, botnets, or open proxies.
• Self-removal option: Many CBL listings allow for self-removal once the spamming activity has ceased and the cause of the compromise is resolved.
• Root cause resolution: Successful delisting requires not just stopping the spam, but demonstrably fixing the underlying vulnerability or misconfiguration.
• Port security: Proper security of outbound SMTP ports, particularly port 25, is critical to prevent unauthorized use and spam relays.
• Reverse DNS: Accurate reverse DNS (PTR records) is a standard requirement for legitimate mail servers and helps avoid being flagged as suspicious. This is a key part of technical solutions for deliverability.

Key considerations

• Compromised servers: If Bluehost IPs are listed due to Microtik routers, it suggests a compromised server or network device that is being used to send spam, requiring immediate investigation by the hosting provider or client's IT.
• Authentication standards: Implement and enforce email authentication protocols like SPF, DKIM, and DMARC across all sending domains to verify legitimate sending sources. A comprehensive guide to DMARC, SPF, and DKIM can be found here.
• Centralized sending: Documentation often implies that having fewer, well-managed sending sources is preferable for reputation management over a dispersed, uncoordinated multi-ESP setup.
• Warm-up best practices: For any new sending infrastructure, follow careful warm-up procedures to establish a positive sender reputation with mailbox providers, even with engaged lists.