How to Check if Your Domain Is Blacklisted

Short answer: Look up your root domain in Spamhaus's IP and Domain Reputation Checker at check.spamhaus.org, then separately look up the public IP your mail actually leaves from. Those two checks take about ninety seconds and cover the listings that genuinely move the needle. If both come back clean and your mail is still landing in spam, you don't have a blocklist problem: open Google Postmaster Tools and Microsoft SNDS and look at your spam complaint rate, because for B2B cold email the receiving provider's private opinion of you matters far more than any public list.

Last updated July 2026.

Every deliverability panic starts the same way. Reply rates fall off a cliff, someone runs a "check 100+ blacklists" tool, it lights up red on four obscure lists nobody has used since 2011, and the team spends a week filing removal requests that change nothing. Meanwhile the actual cause, a 1.4% complaint rate on a list scraped six months ago, sits untouched in Postmaster Tools.

How do I know if my domain is blacklisted?

Enter your sending domain at check.spamhaus.org, the free lookup Spamhaus points to from its own Domain Blocklist documentation. It reports whether the domain appears in the DBL. Then run the same check on your outbound IP. A clean result on both means no meaningful public listing exists, and your delivery problem lives somewhere else.

Two details trip people up. First, the DBL lists domains only, never IP addresses, so a domain lookup and an IP lookup are genuinely different queries against different data. Second, spammers commonly use a clean-looking "From" domain while the tracking or landing-page domain in the message body is the one that gets listed. Check every domain that appears anywhere in your emails: the sending domain, the link-tracking domain, the redirect domain, and the website you're driving people to. URI blocklists like SURBL and URIBL exist specifically to catch domains in message bodies regardless of which IP sent the mail.

Domain, IP, or both: what you are actually checking

A DNSBL query answers one narrow question about one identifier, and there are three identifiers in play. They fail independently.

The domain is yours. You control its DNS, and its reputation follows it wherever you send from. It is the identifier that matters most, and the one a domain blocklist check covers.

The sending IP may or may not be yours. If you run your own SMTP server on a VPS, that IP is yours alone and an IP listing is your problem to fix. If you send through Google Workspace, Microsoft 365, or any shared ESP, the outbound IP belongs to a pool shared with thousands of tenants. You cannot get it delisted and you are not the reason it got listed, so checking it against a DNSBL tells you almost nothing about your own problem. This is one of the trade-offs in how you build your cold email infrastructure: dedicated IPs give you control and blame, shared pools give you neither.

The provider's internal reputation score is invisible from outside. Gmail and Outlook continuously score your domain, your IP, your content and your recipient engagement. That score is not published and not queryable by any third-party checker, and it is what actually decides placement. No public blocklist has veto power over Gmail. Gmail's own model does.

The blocklists a US B2B sender should actually care about

There are hundreds of DNSBLs. Perhaps six matter. Here is the honest ranking, verified against each operator's own documentation.

Blocklist	Who runs it	What it lists	How much it actually affects inbox placement	How to request removal
Spamhaus DBL	The Spamhaus Project	Domain names with poor reputation, including domains used in phishing, fraud and malware distribution. Domains only, no IPs.	Severe. The single most consequential listing for a cold email domain, and widely consumed by corporate filters.	Free, through the reputation checker at check.spamhaus.org. Spamhaus states there is never any charge or fee for removing a listing.
Spamhaus SBL	The Spamhaus Project	IP addresses identified as malicious: spam operations, snowshoe setups, malware and botnet hosting. Typically 30,000 to 40,000 listings.	Severe for the listed IP, but usually a hosting provider issue rather than a sender issue.	End users cannot self-remove. The ISP or host controlling the IP must fix the abuse and submit the request.
Spamhaus CSS	The Spamhaus Project	An automated subset of the SBL covering low-reputation static spam emitters, snowshoe operations and compromised hosts. Normally 2 to 4 million listings.	High. This is the one that catches cold email senders running many small IPs.	Self-service removal is allowed, but Spamhaus warns the IP will be relisted immediately if the underlying problem persists.
Spamhaus PBL	The Spamhaus Project	IP ranges that should not be sending mail direct-to-MX, mostly consumer broadband and dynamic allocations. Covers over 1.4 billion IPv4 addresses.	Only relevant if you are sending from a residential or unconfigured IP, which you should not be doing anyway.	Self-service exclusion for a single static IP with correct forward and reverse DNS. Spamhaus notes user exclusions expire after one year.
SURBL	SURBL BV	Domains of malicious or abused websites that appear in message bodies, filtered independently of the sending IP.	Moderate to high. Catches you when your link or tracking domain is the problem rather than your sender domain.	Via SURBL's lookup and removal process on surbl.org.
URIBL	URIBL.com	Domains used by spammers that appear in URIs inside bulk mail. Public zones include black, grey, red and multi.	Moderate. A black.uribl.com hit is worth acting on; a red zone hit often just means a newly registered or privacy-protected domain.	Register an account on uribl.com and submit a delisting request through the admin portal.
Barracuda BRBL	Barracuda Networks	IP addresses flagged by Barracuda's automated reputation system.	Moderate, and concentrated at organizations running Barracuda appliances. Little effect on Gmail or Outlook.	Form at barracudacentral.org. Barracuda states requests are typically investigated and processed within 12 hours if a valid explanation is provided.
Invaluement (ivmSIP, ivmURI)	Invaluement	IPs sending only spam or very high spam volume, plus domains and URIs found in spam. Positioned as a complement to Spamhaus.	Moderate. Used by a meaningful slice of filtering vendors, so worth checking if Spamhaus is clean but mail still bounces.	Delist request form on invaluement.com.
SORBS	Formerly Proofpoint	Nothing. SORBS was decommissioned on June 5, 2024 and its zones no longer contain reputation data.	None. Ignore any checker that still reports a SORBS status.	Not applicable, the service is dead.

That SORBS row is the tell. Plenty of "blacklist checker" sites still query dnsbl.sorbs.net and still print a status for it, two years after Proofpoint shut the service down. If a tool reports on a list that no longer exists, treat its other 90 results with the same skepticism. Those aggregators are built to generate alarm, and alarm sells remediation. Our own cold email spam checker and the rest of our email deliverability tools answer the narrower question of whether your setup and content are the problem.

Why did my domain get blacklisted?

Almost always because of what you sent, not how you sent it. The common causes for B2B outbound are hitting spam traps on a stale or scraped list, a high complaint rate from irrelevant targeting, ramping volume too fast on a new domain, and sharing a link or tracking domain with a sender who abused it. Broken authentication rarely causes a listing by itself.

Spam traps are the fastest route to a DBL listing. A recycled trap is an old real address a provider repurposed; a pristine trap never belonged to anyone and can only reach your list through scraping or purchase. If you buy or scrape without verification, read up on what a spam trap is before your next send, not after.

The second cause is volume shape. A domain registered three weeks ago that starts sending 800 messages a day looks exactly like snowshoe spam, which is what the Spamhaus CSS is built to catch. Ramping through a proper email warmup over four to six weeks is the difference between having a reputation history and having none.

Why Postmaster Tools and Microsoft SNDS matter more than most blocklist checks

Here is the part most articles get wrong. For B2B cold email delivered to Workspace and Microsoft 365 tenants, the dominant signal is the receiving provider's own reputation view, not a public list.

Google publishes the threshold directly in its Email sender guidelines: keep the spam rate reported in Postmaster Tools below 0.30%, and Google recommends staying under 0.10% for headroom. Cross 0.3% consistently and Gmail will start routing you to spam regardless of whether a single blocklist has ever heard of you. Nothing on any DNSBL query gives you that number. Only Google Postmaster Tools does.

One limitation matters: Google's documentation states that Postmaster Tools data only applies to messages sent to personal Gmail accounts ending in @gmail.com or @googlemail.com, and that data may be withheld when daily volume is too low to protect user privacy. For a pure B2B sender, Postmaster is therefore a proxy rather than a direct readout. It is still the best proxy available, and a climbing consumer Gmail spam rate means Workspace placement is degrading too.

On the Microsoft side, Microsoft SNDS gives per-IP data for mail to Outlook.com, including complaint rates and trap hits, plus the Junk Email Reporting Program feedback loop. Access requires proving you control the IP range, so it only works for IPs you own. Microsoft has also moved the service: the old sendersupport.olc.protection.outlook.com/snds URL now issues a permanent redirect to the new portal at substrate.office.com, so update stale bookmarks and scripts.

Both are dashboards you watch weekly, not tools you open during a crisis. A spam rate creeping from 0.08% to 0.25% over three weeks is a fixable trend; 0.9% discovered after replies stopped is a domain you may have to retire. The same logic applies to the rest of your stack, where continuous uptime monitoring catches an SMTP host going dark at 3am long before a prospect emails to say your links are broken.

How do I get my domain removed from a blacklist?

Fix the cause first, then request removal through the operator's own form, never a paid intermediary. For Spamhaus, submit through check.spamhaus.org; Spamhaus states plainly that there is never any charge or fee associated with removing any of its listings. Barracuda and Invaluement have their own forms. For an SBL listing on a shared IP, only the ISP that controls the IP can request removal.

The order matters more than the paperwork. Before you file anything, stop the sequence, purge the segment that generated the complaints, verify what remains, and confirm authentication end to end. Request removal while the abuse signal is still running and you will be relisted: Spamhaus says exactly that about CSS listings.

Write the removal note like an engineer, not a lawyer. State what happened, what changed, and what prevents recurrence. "We removed 4,200 unverified contacts imported from a 2024 event list, enabled verification on import, and cut daily volume from 900 to 200 per mailbox" gets processed. "Please remove us, we are a legitimate business" does not.

How long does it take to get delisted?

It depends entirely on the list. Spamhaus says DBL listings are highly automated and most expire on their own once the associated activity stops, and that approved removals are processed within a few minutes, though downstream systems may lag up to 24 hours. CSS listings normally expire three days after the last spam detection. Barracuda states removal requests are typically handled within 12 hours.

PBL exclusions are the outlier worth remembering: Spamhaus notes that user-created exclusions expire after one year, so a self-managed static IP can quietly reappear on the PBL twelve months later if nobody renews it. Set a calendar reminder.

Delisting is not the same as recovery, though. Removal stops the hard blocks. Rebuilding the receiving provider's confidence takes weeks of low-volume, high-engagement sending, and there is no form for that.

Does being on a blacklist always mean my email goes to spam?

No. Effect depends on which list and who consumes it. A Spamhaus DBL listing will cause outright rejections at a large share of corporate mail servers. A listing on a small hobbyist DNSBL that three mail admins use may cost you nothing measurable. Conversely, you can be clean on every public list and still land in spam every time.

That second case is the common one for cold email. Gmail and Outlook rarely reject cold outbound outright; they filter it quietly on engagement, complaint rate, content patterns and domain history. We break those signals down in why cold emails go to spam and in our guide to email sender reputation.

A ten-minute triage sequence

Run these in order the next time placement drops. Stop when you find the answer.

Step	What to check	What a bad result means
1	Sending domain and every link or tracking domain in the DBL, SURBL and URIBL	Real listing. Stop sending immediately and work back to the cause before requesting removal.
2	Outbound IP in Spamhaus ZEN (SBL, CSS, PBL, XBL)	If the IP is yours, fix and delist. If it is a shared provider pool, it is not actionable by you.
3	SPF, DKIM and DMARC alignment on a live test message	Authentication failures do not usually cause listings but will suppress placement on their own.
4	Postmaster Tools spam rate and domain reputation	Anything above 0.3% is the cause, full stop. Cut volume and tighten targeting.
5	SNDS complaint rate, trap hits and filter result for Outlook	Trap hits point at list sourcing. Red filter result means Microsoft is junking you at the edge.
6	Bounce and reply logs by segment and by mailbox	If one list segment or one mailbox is responsible, isolate it rather than treating the whole program.

Nine times out of ten with cold email, the answer is at step four or six, not step one.

Staying off the lists in the first place

Prevention is cheap compared to remediation. Verify every address before it enters a sequence and never import a purchased list. Warm each new domain and mailbox for four to six weeks. Spread volume across mailboxes instead of pushing any single one. Get SPF, DKIM and DMARC set up correctly at the start, including a DMARC policy you actually monitor.

Then own your identifiers. ColdMailer sends through your own SMTP credentials and mailboxes, with warm-up and inbox rotation, so reputation accrues to domains you control rather than a shared pool you cannot delist. Run a domain-level blocklist check monthly alongside a periodic email deliverability audit, and start with our guide to cold email deliverability for the broader framework.

FAQ

Can I check if my domain is blacklisted for free?

Yes. Spamhaus's reputation checker is free for manual lookups, SURBL and URIBL both offer free lookup pages, and Postmaster Tools and SNDS are free once you verify ownership. Nothing in the basic diagnostic path costs money, and Spamhaus states it never charges for removal.

Is my domain blacklisted if my emails are going to spam?

Usually not. Landing in spam is far more often caused by a high complaint rate, weak engagement, poor targeting or missing authentication than by a public listing. Check the lists first because it takes two minutes, but expect the real cause to be in your Postmaster Tools spam rate.

Should I just buy a new domain instead of getting delisted?

Only as a last resort, and never for your primary company domain. Burning and replacing domains is the behavior pattern that gets senders listed faster, since rapid domain churn is a snowshoe signal. If the listing came from a fixable list-hygiene problem, fix it and delist. If you rotate domains without changing your sourcing, the new domain gets listed too.

Does a blacklisted IP affect my domain reputation?

Indirectly. Gmail and Outlook track domain and IP reputation separately, but sustained sending from a listed IP produces the blocks and complaints that then damage the domain. The reverse applies on shared infrastructure: a bad neighbor can suppress your placement even when your domain is spotless, which is the argument for dedicated sending infrastructure once volume justifies it.

How to Check if Your Domain Is Blacklisted (and What Actually Matters)