Email Blocklist
Email blocklists are databases of senders (IPs, domains) identified as sources of spam or abuse — used by ESPs and spam filters for blocking decisions — landing on major blocklists severely damages email deliverability requiring rehabilitation.
Why This Matters
Major email blocklists: Spamhaus (most influential), Barracuda, SpamCop, Invaluement, and dozens of smaller lists. Blocklist landing triggers: high spam complaint rates, sending to spam traps, abrupt volume increases (suggesting compromised account or list purchase), and content patterns matching spam signatures. Blocklist impact: ESPs check blocklists during inbox placement decisions; major blocklist landing causes 30-90%+ deliverability loss. Removal processes: contact blocklist operator, demonstrate corrected practices, request removal, sometimes wait period required. Prevention through sustained good practices is far cheaper than rehabilitation.
Frequently Asked Questions
Frequently Asked Questions
What causes senders to land on blocklists?
High complaint rates (spam reports), sending to spam traps (abandoned addresses converted to traps), purchased list usage (often contains traps), sudden volume spikes (suspicious patterns), poor authentication (failed SPF/DKIM/DMARC), and content patterns matching spam signatures.
How is blocklist removal accomplished?
Each blocklist has specific removal process — typically requires demonstrating corrected sending practices, may include wait periods, sometimes requires direct contact with blocklist operator. Removal not guaranteed; severe violations may result in permanent listing.