Major Blocklists & Services

What is Spamhaus (ZEN, DBL, etc.)? What is SURBL? What is URIBL? What is Barracuda Reputation Blocklist? What is Proofpoint? What is Invaluement? What is Lashback? What is Spamcop? What is Cloudmark CSI? What is Return Path Certification (vs blocklisting)? How does Microsoft SNDS relate to blocklisting? How do security vendors integrate with DNSBL data? What is a "URI-based" blocklist and how is it triggered? What is the impact of being on multiple blocklists? How do blocklists detect cold domains? What should I do before requesting removal from any blocklist? Complete blocklist impact reference: Which lists matter most? What is SORBS and how do I get delisted? What is the CBL (Composite Blocking List) and how do I get delisted? What is UCEPROTECT and why is it controversial? What is Spamhaus PBL and is it a bad listing? What is Abusix Mail Intelligence? What is Mailspike? What is Sender Score and how does it relate to blocklisting? What is SpamRats and its specialized lists? What is PSBL (Passive Spam Blocklist)? What is DroneBL? What is Backscatterer? What is blocklist.de? What are the abuse.ch blocklists? What is Cymru Bogons? What is WPBL? What is 0spam (Fusionzero)? Quick reference: Low-impact blocklists you may encounter Which blocklists have shut down or are defunct? What are Spamhaus CSS and DROP lists? What domain blocklists (DBLs/RHSBLs) should I monitor? How do I set up automated blocklist monitoring? Complete blocklist directory: All major IP and domain blocklists with lookup and delisting URLs