Summary
Bounces related to Spamhaus SBL/XBL database listings are caused by a combination of factors including poor sending practices, compromised servers, recipient server issues, and spam complaints. Troubleshooting involves identifying the root cause of the listing, securing the sending server, improving list hygiene, implementing email authentication (SPF, DKIM, DMARC), and following Spamhaus's delisting process. Proactive reputation management, monitoring, and maintaining engaged subscribers are also crucial for avoiding blocklists.
Key findings
- Poor Sending Practices: Lack of email authentication, emailing purchased lists, and not obtaining explicit consent contribute to Spamhaus listings.
- Compromised Servers: Infected servers with malware, vulnerable scripts or plugins, or compromised accounts sending spam result in blocklisting.
- List Hygiene Problems: Inactive subscribers, outdated data, and lack of proper list hygiene practices increase the risk of spam complaints.
- Recipient Server Issues: Misconfigured recipient servers or stale blocklist data on their end can cause bounces.
- Spam Complaints Impact: High spam complaint rates directly contribute to being added to Spamhaus SBL.
Key considerations
- Authentication Implementation: Implement SPF, DKIM, and DMARC to verify sender identity and improve email deliverability.
- Server Security Measures: Regularly update software/plugins, use strong passwords, and monitor for suspicious activity to prevent compromises.
- List Management Best Practices: Practice good list hygiene, ensure explicit opt-in, and provide easy unsubscribe options.
- Proactive Monitoring of Reputation: Monitor IP/domain reputation and set up alerts for blocklist listings to quickly address issues.
- Understand Delisting Process: Familiarize with Spamhaus's delisting process and follow it carefully after resolving the underlying problem.
- Engaged Subscribers Acquisition: Focus on acquiring/retaining engaged subscribers to reduce complaint rates.
Spamhaus
0Spam
Cisco
NoSolicitado
Spamikaze
URIBL
abuse.ro
ALPHANET
Anonmails
Ascams
BLOCKEDSERVERS
Calivent Networks
EFnet
JustSpam
Kempt.net
NordSpam
RV-SOFT Technology
Scientific Spam
SpamRATS
SPFBL
Suomispam
System 5 Hosting
Team Cymru
Validity
www.blocklist.de Fail2Ban-Reporting Service
ZapBL
2stepback.dk
Fayntic Services
ORB UK
technoirc.org
TechTheftSpamhaus0SpamCiscoNoSolicitadoSpamikazeURIBLabuse.roALPHANETAnonmailsAscamsBLOCKEDSERVERSCalivent NetworksEFnetJustSpamKempt.netNordSpamRV-SOFT TechnologyScientific SpamSpamRATSSPFBLSuomispamSystem 5 HostingTeam CymruValiditywww.blocklist.de Fail2Ban-Reporting ServiceZapBL2stepback.dkFayntic ServicesORB UKtechnoirc.orgTechTheftSpamhaus0SpamCiscoNoSolicitadoSpamikazeURIBLabuse.roALPHANETAnonmailsAscamsBLOCKEDSERVERSCalivent NetworksEFnetJustSpamKempt.netNordSpamRV-SOFT TechnologyScientific SpamSpamRATSSPFBLSuomispamSystem 5 HostingTeam CymruValiditywww.blocklist.de Fail2Ban-Reporting ServiceZapBL2stepback.dkFayntic ServicesORB UKtechnoirc.orgTechTheftSpamhaus0SpamCiscoNoSolicitadoSpamikazeURIBLabuse.roALPHANETAnonmailsAscamsBLOCKEDSERVERSCalivent NetworksEFnetJustSpamKempt.netNordSpamRV-SOFT TechnologyScientific SpamSpamRATSSPFBLSuomispamSystem 5 HostingTeam CymruValiditywww.blocklist.de Fail2Ban-Reporting ServiceZapBL2stepback.dkFayntic ServicesORB UKtechnoirc.orgTechTheftSpamhaus0SpamCiscoNoSolicitadoSpamikazeURIBLabuse.roALPHANETAnonmailsAscamsBLOCKEDSERVERSCalivent NetworksEFnetJustSpamKempt.netNordSpamRV-SOFT TechnologyScientific SpamSpamRATSSPFBLSuomispamSystem 5 HostingTeam CymruValiditywww.blocklist.de Fail2Ban-Reporting ServiceZapBL2stepback.dkFayntic ServicesORB UKtechnoirc.orgTechTheftWhat email marketers say
8 marketer opinions
Spamhaus SBL/XBL listings leading to bounces are often caused by poor sending practices, compromised servers, or outdated data. Troubleshooting involves identifying the root cause (compromised accounts, vulnerable scripts, spam complaints), securing the server, improving list hygiene, authenticating email, and following Spamhaus's delisting process. Proactive reputation management and monitoring are also crucial.
Key opinions
- Poor Sending Practices: Lack of email authentication (SPF, DKIM, DMARC), emailing purchased lists, and not obtaining explicit consent can lead to Spamhaus listings.
- Compromised Servers: Compromised accounts, vulnerable scripts or plugins, and malware infections on the sending server can result in spam being sent, leading to blocklisting.
- List Hygiene: Poor list hygiene, including inactive subscribers and outdated data, increases the likelihood of spam complaints and bounces, contributing to blocklist inclusion.
- Recipient Server Issues: In some cases, bounce messages related to Spamhaus may stem from misconfigured recipient servers or stale blocklist data on their end.
Key considerations
- Authentication: Implement SPF, DKIM, and DMARC to verify the sender's identity and improve email deliverability.
- Security: Regularly update software and plugins, use strong passwords, and monitor server activity to prevent compromises.
- List Management: Practice list hygiene by removing inactive subscribers, ensuring explicit opt-in, and providing easy unsubscribe options.
- Monitoring: Proactively monitor IP and domain reputation using tools like GlockApps, and set up alerts for blocklist listings to address issues promptly.
- Delisting Process: Understand and follow Spamhaus's delisting process, including resolving the underlying issue and providing evidence of remediation.
Marketer view
Email marketer from StackOverflow explains that to get delisted from Spamhaus, you must first resolve the issue causing the listing. Then, follow Spamhaus's delisting process, which may involve submitting a request and providing evidence of remediation.
30 Mar 2023 - StackOverflow
Marketer view
Email marketer from Sendinblue explains that Spamhaus listings can cause hard bounces. They advise implementing proper list hygiene, removing inactive subscribers, and ensuring recipients have explicitly opted-in to receive emails.
24 Jul 2024 - Sendinblue
What the experts say
6 expert opinions
Bounces related to Spamhaus SBL/XBL listings can stem from several factors including: badly configured servers, stale blocklist data on the recipient side, and spam complaints. Addressing these issues requires proactive reputation management, ensuring proper blocklist implementation, and focusing on acquiring engaged subscribers. Checking that rejection messages include the correct TXT record is important, and monitoring IP and domain reputation helps to identify and resolve problems quickly.
Key opinions
- Server Configuration Issues: Badly configured servers or stale local SBL sync on the recipient side can lead to incorrect blocking of legitimate emails.
- Spam Complaints: High complaint rates are a primary cause for being added to Spamhaus SBL, emphasizing the importance of ethical list management practices.
- Reputation Management: Proactive reputation management, including monitoring IP and domain reputation, is essential for avoiding blocklists.
- Blocklist Implementation: Properly implemented blocklists should include TXT records in rejection messages; absence indicates potential misconfiguration.
Key considerations
- Proactive Monitoring: Regularly monitor IP and domain reputation to detect and address potential issues early on.
- Ethical List Management: Use double opt-in, avoid purchased lists, practice list hygiene, and provide easy unsubscribe options to minimize spam complaints.
- Verification of Rejection Messages: Ensure rejection messages include TXT records from blocklist lookups to confirm proper implementation of blocklists.
- Subscriber Engagement: Focus on acquiring and retaining engaged subscribers to reduce complaint rates and maintain a positive sending reputation.
Expert view
Expert from Email Geeks shares that over the last few months, Spamhaus has been turning off open resolver access. Some badly configured servers are incorrectly blocking mail. If the IPs aren’t listed at Spamhaus, that’s likely the problem. These domains are likely not getting much of their mail, so they’re unlikely to be important for either the recipient or the senders.
5 Feb 2025 - Email Geeks
Expert view
Expert from Email Geeks explains that if the rejection message doesn’t include the TXT record from blocklist lookup, one should think twice about whether it’s correctly implemented. In the case of Spamhaus that includes a URL.
21 Feb 2025 - Email Geeks
What the documentation says
6 technical articles
Bounces from Spamhaus SBL/XBL listings typically indicate that your IP address has been flagged for spamming, malicious activity, or being infected with malware. Troubleshooting involves identifying and resolving the cause (e.g., compromised accounts, vulnerable scripts), securing your server, and following Spamhaus's delisting procedure. Implementing SPF and DKIM records helps prevent emails from being flagged as spam.
Key findings
- SBL Listing: The Spamhaus Block List (SBL) includes IP addresses involved in spamming or other malicious activities.
- XBL Listing: The Exploit Block List (XBL) lists IP addresses infected with bots, viruses, trojans, or other malware.
- Compromised Servers: Spamhaus listings often result from compromised servers sending spam.
- Email Authentication: Using SPF and DKIM records can help prevent emails from being flagged as spam.
- NDRs: Non-Delivery Reports (NDRs) referencing Spamhaus indicate the recipient's server is blocking your IP due to a Spamhaus listing.
Key considerations
- Check Spamhaus: Check the listed IP on the Spamhaus website to understand the reason for the listing and the delisting process.
- Secure Server: Identify the cause of the spam, secure the server, and then request delisting from Spamhaus.
- Implement SPF/DKIM: Configure SPF and DKIM records to help prevent your emails from being flagged as spam.
- Delisting Procedure: Follow Spamhaus's delisting procedure after resolving the issue causing the listing.
- Contact Recipient's IT: Contact the recipient's IT department or email provider to request whitelisting or investigate the cause of the listing.
Technical article
Documentation from cPanel explains that using SPF and DKIM records helps prevent your emails from being flagged as spam, reducing the likelihood of bounces related to blocklists like Spamhaus. They provide instructions on how to configure these records in cPanel.
19 Jan 2023 - cPanel Documentation
Technical article
Documentation from Postfix explains that correctly configuring SPF (Sender Policy Framework) records is crucial for email authentication and preventing your emails from being marked as spam. It provides guidance on creating and implementing SPF records for Postfix mail servers.
23 Aug 2023 - Postfix
Besides Spamhaus, what blocklists are important for email marketers to monitor?
Can 'invalid recipient' bounce messages be false positives and what should I do about it?
How can I get delisted from Spamhaus?
How can I get help with a Spamhaus listing delisting?
How can I report fraudulent emails and domains to Spamhaus and other relevant organizations?
How do I check Spamhaus for my IP address and understand the listings?
