Summary
AWS hostnames are blacklisted primarily due to spam activity, either originating directly from the user's AWS setup or due to the actions of other bad actors sharing the AWS infrastructure. dblack listings specifically target hostnames appearing in email bodies. Addressing the root cause, which might involve compromised accounts, script vulnerabilities, or poor email sending practices, is crucial for resolving the issue. Security measures like strict outbound filtering, SPF, DKIM, and DMARC records, strong access controls, and regular monitoring of AWS resources are essential to prevent blacklisting. Delisting from blacklists is possible once the spam activity has ceased. Using a custom hostname rather than the default AWS hostname for images and other content is also recommended. Tools are also available to analyse email content to ensure you have gained correct permissions to send emails, and you are not triggering spam filters.
Key findings
- Blacklisting Causes: Spam activity, malware distribution, botnet command and control, compromised servers, and poor IP reputation are major causes for AWS hostname blacklisting.
- Hostname Importance: Using your own hostname rather than the default AWS one is crucial for better email deliverability and avoiding shared reputation issues.
- dblack Listings: dblack specifically lists hostnames that appear within the body of the email message.
- Security Practices: Implementing strict outbound filtering, SPF, DKIM, and DMARC records, and regularly monitoring AWS resources are vital for preventing blacklisting.
- Infrastructure Issues: Sometimes, entire AWS blocks are blacklisted due to other bad actors within the shared infrastructure, making it not always directly the user's fault.
Key considerations
- Investigate and Remediate: If blacklisted, investigate the source of the problem (compromised account, script vulnerability) and take steps to remediate the issue (patch vulnerabilities, change passwords).
- Implement Security Measures: Implement robust security measures like strict outbound filtering, SPF, DKIM, and DMARC records to prevent spoofing and improve deliverability.
- Regular Monitoring: Regularly monitor AWS resources for unusual network activity and potential security threats that could lead to blacklisting.
- Delisting Process: Follow the specific delisting procedure outlined by the blacklist provider once the spam activity has ceased.
- Contact Support: If you suspect unfair blacklisting, contact your ISP or hosting provider for assistance in investigating the issue and potentially speeding up delisting.
- Permissions and Content: Analyse email content and check to see if you have correct permissions from users before sending emails.
What email marketers say
10 marketer opinions
AWS hostnames are often blacklisted due to spam activity originating from the hostname itself, or other bad actors using the AWS infrastructure. Resolution involves identifying the source of the problem (compromised accounts, vulnerabilities, etc.), implementing security measures (SPF, DKIM, DMARC, access controls), using your own hostname instead of AWS defaults, and monitoring AWS resources for unusual activity. Delisting can be requested, but is only effective after the spam activity has ceased. Furthermore, if sending permission isn't gained, and users mark emails as spam, this damages reputation and can also cause blacklisting issues.
Key opinions
- Source of Blacklisting: AWS hostnames get blacklisted due to spam activity, either directly from your actions or from other users on the shared AWS infrastructure.
- Hostname Usage: Using default AWS hostnames in email bodies can lead to blacklisting due to shared reputation issues. Its recommended to use your own hostname.
- Delisting Process: Delisting from blacklists is possible but requires addressing the root cause of the spam activity and ensuring it has stopped.
- Sending Permissions: One of the key reasons for hostnames to get blacklisted is due to lack of sending permission, with users marking emails as spam.
Key considerations
- Security Implementation: Implement SPF, DKIM, and DMARC records to prevent spoofing and improve email deliverability. Review security configurations and implement access controls.
- Resource Monitoring: Regularly monitor AWS resources for unusual network activity using AWS CloudWatch and other monitoring tools.
- Remediation Steps: Investigate immediately to identify the source of the problem (compromised account, script vulnerability, etc.). Once identified, take steps to remediate the issue, such as patching vulnerabilities and changing passwords.
- Contacting Support: If you suspect your AWS hostname has been unfairly blacklisted, contact your internet service provider (ISP) or hosting provider for assistance.
Marketer view
Email marketer from CloudCommunity.com recommends regularly monitoring your AWS resources for unusual network activity. Use AWS CloudWatch and other monitoring tools to detect and respond to potential security threats that could lead to blacklisting.
8 Apr 2024 - CloudCommunity.com
Marketer view
Email marketer from EmailAdminForums.net states it is imperative to implement SPF, DKIM, and DMARC records for your domain to help prevent spoofing and improve email deliverability. This can help to prevent your AWS hostname from being associated with spam activity.
8 May 2025 - EmailAdminForums.net
What the experts say
6 expert opinions
AWS hostnames are blacklisted for appearing in email bodies (dblack listing) and are often related to poor IP reputation due to spam complaints and unsolicited emails. Using your own hostname is crucial. To check for wildcard listings, search for random words plus the listed part. Blacklists are real-time databases that prevent emails from suspected spammers from being delivered.
Key opinions
- Hostname Listing: dblack lists hostnames appearing in email bodies.
- Hostname Customization: Using your own hostname is crucial instead of relying on default AWS hostnames.
- Wildcard Listings: Wildcard listings, where entire subdomains are blocked, can be identified by searching for unique strings within the subdomain.
- IP Reputation: Poor IP reputation from spam complaints significantly contributes to blacklisting.
- Blacklist Definition: Blacklists are real-time databases used to prevent spam and email fraud, leading to undelivered emails.
Key considerations
- Hostname Monitoring: Regularly check if your hostname appears on any blacklists.
- IP Reputation Management: Actively manage your IP reputation by preventing spam and addressing user complaints.
- Email Content Review: Ensure email content does not trigger spam filters or lead to blacklisting.
- AWS Configuration: Configure AWS settings to minimize the risk of being flagged as a source of spam.
- Host Images: When hosting images ensure they are hosted on your own domain.
Expert view
Expert from SpamResource.com explains that IP reputation, influenced by factors such as spam complaints, is a significant determinant for blacklisting. AWS IPs, if used for sending unsolicited emails, can quickly damage their reputation and lead to blacklisting.
11 Mar 2023 - SpamResource.com
Expert view
Expert from Email Geeks says that you don’t need to change where you host the images, you just need to use your own hostname.
12 Jun 2022 - Email Geeks
What the documentation says
5 technical articles
AWS hostnames are blacklisted due to spam activity, malware distribution, or botnet command and control originating from them. Common causes include compromised servers within the AWS infrastructure. Solutions involve implementing strict outbound filtering, monitoring outbound traffic, securing instances, and using tools like Spamhaus Block List (SBL) to check for listings and follow delisting procedures. Tools like Debouncer can help analyze email quality and identify issues leading to blacklisting.
Key findings
- Reasons for Listing: Hostnames are listed due to spam, malware, or botnet activity originating from or advertised via the hostname.
- Compromised Servers: A common cause is compromised servers within AWS sending spam.
- Importance of Monitoring: Monitoring outbound traffic is crucial to identify and mitigate abuse.
- Delisting Tools: Spamhaus Block List (SBL) can be used to check if your hostname is listed.
- Email Quality Analysis: Tools like Debouncer can analyze email quality and identify issues.
Key considerations
- Outbound Filtering: Implement strict outbound filtering to prevent compromised instances from sending abusive content.
- Security Measures: Secure AWS instances to prevent them from being compromised.
- Proactive Monitoring: Proactively monitor outbound traffic for unusual patterns.
- Delisting Process: Follow the delisting procedure outlined by the blacklist provider if your hostname is listed.
- Analyse Email Content: Use email quality tools to check the reasons why your email content might be marked as spam.
Technical article
Documentation from Debouncer.com says that a good idea is to use a tool like Debouncer, which can help analyse your email quality, and advise on setup and content issues that may cause your emails to be marked as spam or for your hostnames to be blacklisted.
16 Sep 2023 - Debouncer.com
Technical article
Documentation from Abusix.com explains that a hostname might be listed due to spam activity originating from or being advertised via that hostname. This includes but is not limited to, unsolicited email, malware distribution, and botnet command and control.
18 Sep 2022 - Abusix.com
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