Blocklist
A list of IP addresses, domains or hashes judged to send spam or abuse, which receiving systems query to block or score mail. Blacklist is the older name.
What it means
Spamhaus defines a blocklist as a database of IP addresses, domains or hashes, compiled by research teams that have seen the listed resources involved in malicious behaviour (spam, malware, botnets, phishing) or associated with a bad reputation, and published in a DNS zone so anyone running mail infrastructure can use it. Most email blocklists are published that way, as DNSBLs.
Several words are in use for the same thing. Spamhaus says blocklist, SpamCop says blocking list, M3AAWG documents use both blocklist and blacklist, and RFC 5782 (2010) says blacklist.
What a listing costs you depends on who queries the list: Spamhaus says its data protects billions of mailboxes, while a small list may be used by few receivers. Some lists expire listings automatically (SpamCop's is time-based); others need a removal request.
Related terms
On this site
Sources
What this definition rests on. The wording is ours; the facts are theirs.
- Spamhaus FAQ: General definitionsspamhaus.org
- RFC 5782: DNS blacklists and whitelistsrfc-editor.org
- SpamCop Blocking Listspamcop.net
- M3AAWG: Help! I hit a spam trap! (February 2023)m3aawg.org
All 432 terms in the glossaryThe wiki: blocklists and bounce codes