Free Tools
Email Blacklist Checker
Check if your domain or IP address is listed on any of the 21 most common email blacklists. Instant results — no sign-up required.
The fix starts with reputation
Getting off a blacklist is only half the battle.
Blacklists list IPs with poor sender reputation. The long-term fix is building real credibility — and that means real engagement from real-looking personas, not fake pings or self-sends.
MailStrike warms your domain using a network of AI-driven personas that open, reply to, and positively engage with your emails. Mail providers see consistent, human-like behaviour and update your reputation accordingly — keeping you out of spam and off blacklists before it becomes a problem.
What is a DNS blacklist?
A DNS blacklist (DNSBL) is a list of IP addresses or domains that have been flagged for sending spam, hosting malware, or exhibiting other abusive behaviour. Receiving mail servers query these lists in real time to decide whether to accept, flag, or reject incoming email.
If your sending IP appears on a major blacklist like Spamhaus ZEN or SpamCop, your emails may never reach the inbox — even if your content and authentication are perfect. Blacklist checks should be a routine part of any email deliverability audit.
How blacklist checking works
Enter your domain or IP
If you enter a domain name, it's resolved to its IPv4 address first. If you enter an IP directly, it's used as-is.
IP octets are reversed
The IP address is reversed (e.g. 1.2.3.4 becomes 4.3.2.1) — this is the standard DNSBL query format.
21 lookups run in parallel
Each blacklist is queried by appending the reversed IP to the blacklist's zone (e.g. 4.3.2.1.zen.spamhaus.org). All 21 queries run simultaneously.
Results decoded
An NXDOMAIN response means the IP is not listed (clean). Any A record returned means it's listed — the returned IP often encodes the reason for the listing.
Blacklist tiers explained
Not all blacklists carry equal weight. A listing on Spamhaus ZEN will block your email at nearly every major provider. A listing on a Standard-tier list may have minimal impact on most recipients.
Queried by Gmail, Outlook, Yahoo, and virtually every commercial mail server. A listing here will cause immediate and widespread delivery failures. Treat as urgent.
Widely adopted by corporate email gateways and regional providers. Listings here will cause significant delivery problems and should be resolved promptly.
Used by a smaller subset of mail servers. Impact varies. Note that UCEPROTECT Level 2 and 3 list entire netblocks and ASNs — a listing there may not reflect your own sending behaviour.
How to fix a blacklist listing
Getting delisted is a two-step process: remove the immediate listing, then fix the underlying reputation problem so it doesn't happen again.
Identify and fix the root cause
Stop whatever triggered the listing — a compromised server, a spam complaint spike, an infected machine sending outbound spam, or a purchased list. No delisting request will stick if the problem is still active.
Submit a delisting request
Most major blacklists (Spamhaus, SpamCop, Barracuda) have self-service removal tools. Visit the blacklist's website, look up your IP, and follow their removal process. Expect 24–72 hours for propagation.
Authenticate your email properly
Ensure SPF, DKIM, and DMARC are all configured and passing. Unauthenticated email is far more likely to be re-listed. Use our SPF and DMARC generators to check your setup.
Rebuild your sender reputation with persona-based warming
Delisting removes the flag — it doesn't restore your reputation. Mail providers score your IP based on real engagement signals: opens, replies, moves out of spam. Persona-based email warming tools like MailStrike simulate exactly this behaviour at scale, generating authentic engagement from AI-driven personas that look and act like real recipients. This signals to Gmail, Outlook, and others that your domain is trusted — which is what keeps you off blacklists long term.
Frequently asked questions
How do I get removed from a blacklist?
Each blacklist has its own removal (delisting) process. Most require you to identify and fix the root cause first — stop sending spam, patch a compromised server, or remove malware. Once fixed, visit the blacklist's website and submit a delisting request. Spamhaus, SpamCop, and Barracuda all have self-service lookup and removal tools.
Why does my IP appear on UCEPROTECT Level 2 or 3 but not Level 1?
UCEPROTECT Level 2 lists entire IP ranges where too many IPs are sending spam. Level 3 lists entire ASNs (hosting providers). Your IP can be caught by these listings even if you've never sent a single spam message — it's a consequence of sharing infrastructure with other senders. Most major mail servers do not use Levels 2 and 3 for this reason.
My domain is clean but emails are still going to spam. Why?
Blacklist status is just one factor in deliverability. Other common causes include missing or misconfigured SPF/DKIM/DMARC records, low sender reputation from low engagement, spam-triggering content or subject lines, high bounce rates, or sending to disengaged or purchased lists. Use our SPF and DMARC generators to check your authentication setup.
How often should I check my blacklist status?
For active senders, checking weekly is a reasonable baseline. If you're running an email warmup campaign, daily checks during the first few weeks are worthwhile. Check immediately any time you notice an unusual drop in open rates or deliverability metrics.
Why does the check show some blacklists as 'Check failed'?
Some blacklists (particularly SORBS) are intermittently unavailable or slow to respond. A 'Check failed' result means the query timed out or returned a SERVFAIL — it is inconclusive, not necessarily clean. If a specific blacklist consistently fails, check its status page directly.