What is the Another Spam Prevention Early Warning System (ASPEWS) blacklist?

The Another Spam Prevention Early Warning System (ASPEWS) blacklist is used to block email or, in some instances, all network traffic from certain areas of the Internet. If a mailbox provider has spammers on its network and refuses to do anything about it, ASPEWS will block its network. ASPEWS identifies known spammers and spam operations, listing them as soon as they start, sometimes even before they start spamming.

Key details

  • Type of list: This is a public blacklist.
  • Listings occur: At the IP level and are subnet-based. Most listings occur at the hosting or mailbox provider level.
  • Criteria for getting listed: Sending spam.
  • Impact on deliverability: Minimal.
  • Getting removed from this blacklist: ASPEWS does not support requests for manual delisting. IP addresses automatically expire from the list some period of time after the last receipt of spam in their spam traps.

Common issues

Listings on ASPEWS are rare for most reputable senders.  Unless you send via Internet Protocol version 6 (IPv6), you may not see a listing here.

Products affected


Best practices

A listing may not be specifically related to your individual IP address. If you begin to see delivery issues and get error codes indicating a listing on ASPEWS, contact your hosting or mailbox provider to determine who within the network is creating the issue. The hosting or mailbox provider is responsible for fixing the issue.  

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