The term "blackhole" refers to a networking black hole, an expression for a link on a network that drops incoming traffic instead of forwarding it normally.The intent of the RBL was that sites using it would refuse traffic from sites which supported spam — whether by actively sending spam, or in other ways.For the large resource consumption when using software designed as the role of a Domain Name Server, there are role-specific software applications designed specifically for servers with a role of a DNS blacklist.The hard part of operating a DNSBL is populating it with addresses.However, many observers believe the attacks are perpetrated by spammers in order to interfere with the DNSBLs' operation or hound them into shutting down.
An RHSBL lists the domain names used in the "from" or "reply-to" e-mail address.
The locations consist of IP addresses which are most often used to publish the addresses of computers or networks linked to spamming; most mail server software can be configured to reject or flag messages which have been sent from a site listed on one or more such lists.
The term "Blackhole List" is sometimes interchanged with the term "blacklist" and "blocklist".
The very first version of the RBL was not published as a DNSBL, but rather a list of networks transmitted via BGP to routers owned by subscribers so that network operators could drop all TCP/IP traffic for machines used to send spam or host spam supporting services, such as a website.
The inventor of the technique later commonly called a DNSBL was Eric Ziegast while employed at Vixie Enterprises.