DNSBL stands for Domain Name System-based Blackhole List. A DNSBL lists IP addresses, usually those that have been observed by the list operator to send junk e-mails, that are used by applications to decrease the delivery of junk e-mails.
These lists are developed by third-party entities and are not supported or maintained by AISO.Net.
AISO.Net uses SpamAssassin's DNSBLs that SpamAssassin uses for junk e-mail scoring. SpamAssassin uses a scoring system to determine what e-mail is junk e-mail and which e-mail messages are legitimate.
Our e-mail filtering system also uses many other DNSBL to reject junk e-mail messages and to block those addresses that send junk e-mail.
For more information on greylisting click here: http://www.aiso.net/spam-protection.asp