Specific Blacklists

Guides for Spamhaus, Barracuda, SpamCop, and provider-specific blacklists.

All Blacklist Guides Reputation Spam & Filtering Specific Blacklists IP & Blocking Deliverability

Understanding Spamhaus: The Most Important Email Blacklist

Learn how Spamhaus works, what their different blocklists mean (SBL, XBL, PBL, DBL, ZEN), and how to get delisted if you're blocked.

Barracuda Blacklist (BRBL): How to Check and Remove Your IP

Learn how the Barracuda Reputation Block List works, how to check if you're listed, and how to request removal if your IP is blocked.

SpamCop Blacklist: How It Works and How to Get Delisted

Understand how SpamCop's user-reported blacklist works, why you might be listed, and the unique automatic expiration system for getting removed.

AOL Blacklist: How to Fix Blocked Email to AOL Addresses

Learn how AOL (now part of Yahoo) blocks email, common error codes, and how to get unblocked if your emails aren't reaching AOL recipients.

Outlook Blacklist: How Microsoft Blocks Email and How to Fix It

Learn how Microsoft's email filtering works for Outlook, Hotmail, and Live. Understand their blacklist system and how to get unblocked.

Comcast Email Blacklist: How to Fix Blocked Email to Xfinity Addresses

Learn how Comcast/Xfinity blocks email, common error codes you'll encounter, and how to get unblocked if your emails aren't reaching Comcast recipients.

URL Blacklists: How Links Affect Email Deliverability

Understand how URL blacklists work, which lists matter most, and how links in your emails can trigger spam filters even when your sending reputation is clean.