The Axigen Solution: Overview & Architecture

A DNSBL (DNS-based Blackhole List, Block List, or Blacklist) is a list of IP addresses published through the Internet Domain Name Service in a particular format. A blacklist usually refers to a list of email or IP addresses known to send spam emails or some other type of unsolicited messages. Such lists are currently used by mail servers for filtering incoming emails and blocking the ones listed, in order to improve mail security and integrity. The blacklist is also the opposite of what is called a whitelist. Excluding IP or IP ranges from DNSBL checks is also available in Axigen.

Furthermore, a connection is not rejected if the sender is authenticated even if the connecting IP is listed in one of the DNSBL operators used.