// FREE TOOL
Blacklist Checker
No signup. No limits. Same continuous check we run on every managed mailbox.
Which blacklists actually affect placement
Spamhaus is the universal one — virtually every receiver consults it. Barracuda matters for business mail. Most smaller RBLs are checked by almost no one.
How domains get listed
Spam trap hits, complaint rate spikes, volume bursts on new domains, scraped lists, forgetting suppression lists.
How to delist
Each RBL has its own form. Spamhaus and Barracuda require explaining the cause and fix. Don't request removal before fixing the root cause.
Prevention
Warmup ramps, list hygiene, isolation, continuous monitoring.
Common questions
Spamhaus (SBL, XBL, PBL) and Barracuda. Many smaller RBLs are noise — being on one obscure list rarely affects real delivery.
CLAYINBOX runs this check continuously on every domain it manages — automatically.