What should I do if my website is on a Fastly IP range listed on Spamhaus but I don't send email from that IP?

Key findings

• Separate IP concerns: A website's IP being on an email blocklist (like Spamhaus SBL) generally does not affect email deliverability if your emails are sent from a different, dedicated email sending IP address.
• CDN IP ranges: CDN providers such as Fastly, or platforms like GitHub Pages that utilize CDNs, often have large shared IP ranges that can become blocklisted due to spam or malicious activity originating from other users on the same range. This is a common occurrence and not necessarily a reflection on your specific website.
• No direct email impact: If the listed IP address is solely used for serving your website content and not for sending email, its status on an RBL (real-time blacklist) designed for email will generally not cause your legitimate emails to bounce.
• Verify bounce reasons: It is critical to examine the specific bounce messages for any email delivery failures. A bounce explicitly citing a Spamhaus listing for your actual email sending IP is distinct from a website hosting IP blocklist.

Key considerations

• Isolate email infrastructure: Ensure your email sending infrastructure (whether through an ESP or your own servers) is completely separate and properly authenticated with SPF, DKIM, and DMARC to prevent web hosting IP issues from impacting email.
• Monitor email sending IPs: Regularly check the reputation of the specific IP addresses used by your Email Service Provider or your own dedicated sending IPs. You can use a blocklist checker to do this.
• Review SPF policy: While your website's IP might be listed, a robust SPF policy (e.g., using `-all` for hardfail) on your email sending domain helps prevent unauthorized entities from sending mail on your behalf from problematic IPs. Learn more about SPF policy best practices.
• Consider hosting alternatives (long-term): If your CDN or web host's IP ranges are persistently listed and causing collateral issues, or if you plan to send email from that infrastructure in the future, you might consider migrating your website hosting to a provider with better IP hygiene. However, for a static site not sending email, this is rarely an immediate concern. For more context on the Spamhaus SBL, refer to the Spamhaus SBL policy page.

Key opinions

• Initial confusion: Many marketers initially panic and mistake a website hosting IP blocklist for an email sending IP blocklist, leading to unnecessary alarm about their email deliverability.
• Shared IP challenges: Shared IP addresses, whether for web hosting or email sending, are a frequent source of blocklisting due to the actions of other users on the same infrastructure, which can inadvertently affect legitimate users.
• Importance of bounce messages: Checking detailed bounce messages is considered a primary diagnostic step by marketers to correctly identify the true root cause of email deliverability issues, rather than making assumptions based on general blocklist checks.
• Seeking community advice: Many marketers find value in consulting online communities (like Email Geeks) for quick advice and validation when encountering unfamiliar or complex blocklist scenarios.

Key considerations

• Don't jump to conclusions: If your website's IP is listed, but you send email through an Email Service Provider (ESP), do not automatically assume the two issues are related without thoroughly investigating your email bounces. See our guide on why your emails are going to spam.
• Leverage ESP support: If you use an ESP, rely on their support and expertise to manage shared IP reputations and address any deliverability issues stemming from their infrastructure. They are typically equipped to handle blocklist concerns.
• Understand your infrastructure: Marketers should have a clear understanding of which IP addresses are responsible for their website hosting versus their email sending. This distinction is crucial for effective troubleshooting.
• Proactive monitoring: While direct IP monitoring may not always be a marketer's core task, being aware of and encouraging monitoring for their ESP's IPs is beneficial for overall deliverability. This includes understanding what happens when your domain is blocklisted. A helpful resource for understanding shared IP concerns is available on Quora discussions about shared hosting impacts.

Key opinions

• Isolate the issue: Experts confirm that a Spamhaus listing for a web hosting IP range (like Fastly's) generally does not impact email deliverability if emails are sent from a distinct, separate IP address.
• Verify the bounce source: It is paramount to confirm that email bounces are definitively caused by the specific IP in question, and not by other factors or a different sending IP.
• Shared CDN IP reality: Large CDN providers often have broad IP ranges (e.g., /24 subnets) that can become blocklisted due to malicious activities by other users sharing that infrastructure, which is a known industry challenge.
• Limited action for CDN IP: If your website's CDN IP is listed, and you are not using it to send email, experts generally agree there's little direct action you need to take regarding that specific blocklist entry.
• SPF policy refinement: An SPF policy with a "?all" (softfail) mechanism is less secure than a "-all" (hardfail) as it could theoretically allow unauthorized senders to appear legitimate.

Key considerations

• Distinguish IP functions: Always differentiate between the IP address used for web hosting and the one used for email sending, as their respective reputation impacts are distinct. If you are experiencing blocks, you can use our guide to dealing with Spamhaus and other blocklists.
• Analyze full bounce messages: Look at the entire bounce message, not just a summary, to precisely identify the IP address and the specific blocklist or reason causing the delivery problem.
• No need to move hosting solely for CDN blacklist: A CDN IP blocklist, if truly unrelated to your email sending, should not be the sole motivation for changing your web hosting provider.
• Implement strong authentication: Ensure robust email authentication (SPF, DKIM, DMARC) is in place for your email sending domains to protect your sender reputation, irrespective of any issues with your web hosting IP. For more information, you can check the Spamhaus lookup tool directly.

Key findings

• SBL purpose: The Spamhaus SBL (Spamhaus Block List) is explicitly designed to list IP addresses that are known sources of spam or malicious content, aiming to prevent email originating from those IPs. Its focus is on email integrity.
• IP vs. domain listings: Blocklists (or blacklists) differentiate between IP address listings (which affect mail servers) and domain listings (which affect sender domains or URLs found in email content), each having distinct impacts.
• Shared infrastructure implications: Documentation frequently acknowledges that shared IP addresses on large networks, such as those used by CDNs or shared hosting providers, can be listed due to the abusive activities of a subset of their users.
• Non-email traffic: Blocklists like Spamhaus are generally concerned with email or email-related abuse. Therefore, a website's IP being listed does not inherently mean that non-email traffic (like web browsing or content delivery) will be affected.

Key considerations

• Consult the blocklist's website: Always refer to the specific blocklist's official website for accurate details on a listing, including the stated reason and any applicable delisting procedures. The Spamhaus FAQ provides comprehensive information on the Spamhaus SBL.
• Understand listing types: Familiarize yourself with the different types of email blocklists, such as IP-based, domain-based, or policy-based, and their specific intended uses. Our in-depth guide to email blocklists provides a detailed overview.
• CDN role: Content Delivery Networks are optimized for content delivery and web traffic. Their documentation typically indicates they do not handle direct email sending from their IP ranges, which is a key distinction when troubleshooting deliverability.
• SPF and DMARC alignment: Official email standards emphasize that authentication records like SPF, DKIM, and DMARC are crucial for verifying sender identity and preventing spoofing, independently of your web hosting IP's reputation. This is covered further in transitioning your DMARC policy.