Is your domain or IP blacklisted?
Enter a domain or an IPv4 address. The checker queries 21 public blacklists in one pass, from the Spamhaus lists (ZEN, SBL, XBL, PBL and the domain list DBL) to Barracuda, SpamCop and UCEPROTECT, and every listing it finds links to that list's delisting guide. Free, no account.
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 AI Agents with real-looking personas, not fake pings or self-sends.
MailStrike warms your domain using a network of AI Agents that open, reply to, and positively engage with your emails. Mail providers see consistent, human-like behavior and update your reputation accordingly, keeping you out of spam and off blacklists before it becomes a problem.
Which blacklists this checks
18 IP lists, queried with the sending address, and 3 domain lists, queried with the domain name when you enter a domain. The tier is how much a listing costs you; the removal column is how the operator takes an entry off, from the operator's own pages. Each name opens that list's delisting guide.
| List | Checks | Tier | Removal |
|---|---|---|---|
| Spamhaus ZENzen.spamhaus.org | IP | Critical | Self-service |
| Spamhaus SBLsbl.spamhaus.org | IP | Critical | By request |
| Spamhaus XBLxbl.spamhaus.org | IP | Critical | Self-service |
| Spamhaus PBLpbl.spamhaus.org | IP | Major | Self-service |
| SpamCop BLbl.spamcop.net | IP | Major | Expires on its own |
| Barracuda Reputationb.barracudacentral.org | IP | Critical | Self-service |
| CBL Abuseatcbl.abuseat.org | IP | Major | Self-service |
| UCEPROTECT Level 1dnsbl-1.uceprotect.net | IP | Major | Expires on its own |
| UCEPROTECT Level 2dnsbl-2.uceprotect.net | IP | Standard | No removal path |
| UCEPROTECT Level 3dnsbl-3.uceprotect.net | IP | Standard | No removal path |
| PSBLpsbl.surriel.com | IP | Standard | Self-service |
| DroneBLdnsbl.dronebl.org | IP | Standard | By request |
| 0spam BLbl.0spam.org | IP | Standard | Self-service |
| GBUdb Truncatetruncate.gbudb.net | IP | Standard | No removal path |
| IMP Spam RBLspamrbl.imp.ch | IP | Standard | Self-service |
| InterServer RBLrbl.interserver.net | IP | Standard | By request |
| JunkEmailFilter BLblack.junkemailfilter.com | IP | Standard | Self-service |
| DigiBase Spambotspambot.bls.digibase.ca | IP | Standard | By request |
| Spamhaus DBLdbl.spamhaus.org | Domain | Critical | Self-service |
| SURBL multimulti.surbl.org | Domain | Major | Self-service |
| URIBL multimulti.uribl.com | Domain | Major | Self-service |
Not on the list: SORBS, which Proofpoint shut down on 5 June 2024 (a checker that still shows it is reading a dead zone, and the SORBS guide explains what that result means), and the lists that need an account to query, such as Abusix and Invaluement, whose guides are on the delisting hub.
What each result means
Listed
The list returned an address for your query, which means an entry exists. The returned code often names the sublist or the reason (on Spamhaus ZEN, 127.0.0.2 is the SBL and 127.0.0.10 the PBL), and the result links to the list's delisting guide.
Not listed
The list answered that it holds no entry (NXDOMAIN) for the address or domain you checked, today.
Check failed
The list timed out or refused the query. That is inconclusive, not clean: run the check again, or use the operator's own lookup from the list's guide.
Domain or IP?When you enter a domain, the IP lists are checked against the address the domain itself resolves to, which is usually your website's server rather than the one your mail leaves from. To check the sending server, enter its IP: it appears in the Receivedheaders of a message you sent, on the line where the recipient's server names the address it took the message from. On Google Workspace or Microsoft 365 that address belongs to the provider, so for most senders the domain lists are the ones that speak about you.
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 behavior. 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.
All lookups run in parallel
Each IP blacklist is queried by appending the reversed IP to the blacklist's zone (e.g. 4.3.2.1.zen.spamhaus.org). Domain blacklists (Spamhaus DBL, SURBL and URIBL) are queried with the domain name itself, since they list domains rather than sending IPs.
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.
Large providers and mail gateways enforce these lists, so a listing turns into rejected mail rather than spam-foldering. Treat it as the first thing to clear.
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 behavior.
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
Each list has its own process: a request form, a self-service tool, or an entry that expires once the behavior stops. The table above says which, and each list's delisting guide walks the steps and says how long removal takes.
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 agentic warmup
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. Agentic warmup tools like MailStrike simulate exactly this behavior at scale, generating authentic engagement from AI Agents whose personas 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 check if my domain is blacklisted?
Enter the domain above. The checker queries the domain lists (Spamhaus DBL, SURBL and URIBL) with the domain name itself, and the IP lists with the address the domain resolves to, 21 lists in one pass. A listed result names the list and links to its delisting guide.
How do I get removed from a blacklist?
Fix the cause first: stop the spam, patch the compromised server, remove the malware, or clean the list that hit the traps. Then use the list's own removal process. Spamhaus and Barracuda have removal forms, SpamCop and UCEPROTECT Level 1 expire on their own once the reports stop, and some lists have no removal path at all. The table above says which is which, and each list's guide walks the steps.
Why does my IP appear on UCEPROTECT Level 2 or 3 but not Level 1?
UCEPROTECT Level 2 lists whole IP ranges where too many addresses are listed, and Level 3 lists whole provider networks (ASNs). Your IP can be caught by these listings without ever sending spam, because it shares infrastructure with senders who did. The fix sits with your provider, not with you.
My domain is not blacklisted but my emails still go to spam. Why?
A blacklist is one input among several. Missing or failing SPF, DKIM or DMARC, a young domain with no sending history, low engagement, spam complaints, a volume jump, or a list with dead addresses all put mail in spam without any blacklist noticing. The domain reputation checker reads the public part of that; a placement test shows where the mail lands.
Does this checker test SORBS?
No. Proofpoint shut SORBS down on 5 June 2024, and its zones no longer answer, so a SORBS result from any checker says nothing about your IP. The SORBS guide explains what to do if another tool or a bounce message still names it.
Why does the check show some blacklists as 'Check failed'?
The list did not answer in time, or it refused the query. Some operators refuse lookups that arrive through large public DNS resolvers, and a slow list can time out. A failed check is inconclusive, not clean: run it again, or use the operator's own lookup, which each list's guide links.
How often should I check my blacklist status?
For active senders, weekly is a reasonable baseline. During a warmup or right after a volume increase, check daily for the first weeks, and check immediately whenever open rates or replies drop for no visible reason.
Related free tools
SPF Record Generator
Generate a valid SPF TXT record for your domain. Select your email providers and copy the DNS record.
DMARC Record Generator
Set your DMARC policy, configure aggregate reporting, and get a copy-paste DNS record in seconds.
Domain Reputation Checker
Blacklists, SPF, DKIM, DMARC, reverse DNS and domain age in one report, with what to fix first.
Blacklist removal guides
A delisting guide for every list that matters: how serious it is, how removal works, how long it takes.