Blacklist Checker
Articles, guides, and in-depth tips for the Blacklist Checker — everything you need to get the most out of it.
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Your IP Is on a Blacklist — Here's What the Specific List Tells You About Why and What to Do Next
A Clean Blacklist Record Doesn't Mean Gmail Will Deliver Your Email — Here's the Private Reputation System You Can't See
A clean public blacklist record doesn't guarantee inbox delivery — Gmail, Outlook, and Yahoo operate private reputation systems that aren't published, don't have external lookup tools, and use engagement signals (open rates, spam complaint rates, deletes without opening) rather than just IP status. Here's the two-tier reputation system, what Google Postmaster Tools and Microsoft SNDS provide, the IP warm-up requirement, and why clearing DNSBLs is necessary but not sufficient.
Shared IP Blacklisting: How a Neighbor's Compromised Website Tanks Your Email Deliverability
Your domain can land on a spam blacklist without sending a single spam email — if you're on shared hosting, the IP address you share with hundreds of other sites carries one collective reputation, and someone else's compromised WordPress site becomes your deliverability problem. Here's how to recognize shared-IP contamination, what your hosting provider can (and you can't) do about it, and why "IP warming" matters when switching to a dedicated IP.
How DNSBLs Actually Work: The Reversed-IP DNS Query Behind Every Blacklist Check
Checking whether an IP is on a spam blacklist is actually just a specially-formatted DNS query — reversing the IP's octets and appending the blacklist's zone name. Here's how DNSBLs work technically, why different blacklists can disagree about the same IP, and how to interpret listing results based on which lists actually matter for deliverability.
How Gmail Decides Where Your Email Lands: Inbox, Promotions, and Spam Explained
Gmail routes email based primarily on engagement signals — opens, clicks, spam complaints, and whether recipients move messages to Primary. Here's how the three-tier system works, what signals determine Promotions vs. Primary, why list segmentation improves deliverability, and how Outlook differs from Gmail.
How to Get Removed from Email Blacklists: Spamhaus, Barracuda & More
Getting blacklisted is fast; getting off takes knowing which list you're on and following the right delisting process for each. Here's the major blacklists explained, what causes listings, and how to remove your IP or domain from each one.
Blacklist Checker — Is Your IP or Domain on a Spam Blacklist?
Learn how email spam blacklists work, why you might get listed, how to check if your IP or domain is on a blacklist, and how to get removed from the major DNSBLs.
