Blocklist

What is it?

What is it?

A "Blocklist" is a database used by email servers and ISPs to prevent emails from known spam sources or malicious senders from reaching users' inboxes. When an IP address or domain is added to a blocklist, any emails sent from it are automatically filtered or blocked based on the policies of the receiving email system. Blocklists are a critical tool in the fight against spam and email-based threats.

Key points to remember

Key points to remember

  • Dynamic and Diverse: There are many blocklists, each with criteria for listing and delisting IP addresses and domains.

  • Preventive Measure: Being on a blocklist is a preventive measure to protect users from spam, phishing, and other email threats.


  • Check and Remediate: Senders can check if they are on a blocklist and take steps to be removed, usually by proving they have corrected the issues that led to the listing.


  • Impact on Deliverability: Being listed on a blocklist can severely impact email deliverability and sender reputation.


  • Good Email Practices: Adhering to best email practices and monitoring sending reputation can help avoid being listed on a blocklist.

Example of Use

Example of Use

  1. Reputation Management: An e-commerce company regularly checks major blocklists to ensure their sending IP is not listed, maintaining their email deliverability.


  2. Remediation Process: After finding their domain on a blocklist, a marketing agency cleans their email list and improves their sending practices, then requests removal from the blocklist.

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