Free tool
Email Blacklist & Deliverability Checker
Enter a domain and this tool checks it -- and its mail server's IP, where resolvable -- against trusted DNS blocklists used by mail providers worldwide, so you can catch a deliverability problem before it quietly tanks your open rates.
Why blocklist listings matter
Mail providers -- Gmail, Outlook, and most corporate mail servers -- consult DNS blocklists automatically before deciding whether to deliver, quarantine, or silently drop an incoming message. A single listing can mean an entire domain's emails start landing in spam, or never arrive at all, often with no notification to the sender.
How this tool checks deliverability
This tool resolves your domain's mail-relevant IP address and queries a set of well-established blocklist operators -- Spamhaus, Barracuda, SpamCop, and SORBS -- via plain DNS lookups against each operator's own servers. Nothing here ever connects to your domain or mail server directly, so there's no configuration required and no risk to your infrastructure.
IP-based vs. domain-based blocklists
IP-based lists flag the specific server sending mail -- relevant if you run your own mail server or a shared IP got a bad reputation. Domain-based lists flag the domain referenced in email content or return-paths regardless of which server sends it -- the more relevant check if you send through a third-party provider like Mailchimp or Google Workspace.
Deliverability and real collaboration
A domain with deliverability problems struggles to build any relationship that depends on email -- newsletters, outreach, or simple back-and-forth with a prospective partner. PressCircle verifies every member's domain before their profile goes live, so the connections you make here start from a foundation of trust rather than a cold inbox.
Frequently asked questions
What is a DNS blacklist (DNSBL)?
A DNS-based blocklist is a list, maintained by an independent operator, of IP addresses and domains associated with spam. Mail servers around the world check these lists automatically -- being listed on even one can mean your emails get silently dropped or sent to spam.
Which blocklists does this tool check?
Spamhaus ZEN, Barracuda's Reputation Block List, SpamCop, and SORBS for your domain's IP address, plus Spamhaus's Domain Block List for the domain itself -- covering both "your server is flagged" and "your domain is flagged regardless of who sends for you" cases.
What do I do if I'm listed?
Each blocklist operator publishes its own delisting process, usually free and linked from their site once you look up the flagged IP or domain directly. Fix whatever caused the listing first (compromised account, misconfigured mail server, a burst of complaints) or the listing will likely reappear.
Is this free, and how does it work?
Yes, free with no signup. This tool only queries the blocklists' own DNS servers -- it never connects to your domain or mail server directly, so there's nothing to configure and no risk to your infrastructure.