How to Check If Your Domain Is Blacklisted
To check if your domain is blacklisted, run your domain and sending IP through a multi-blacklist lookup tool like MXToolbox or MultiRBL, then confirm inbox placement with Google Postmaster Tools and a seed-list test. A blacklist listing means your emails are being rejected or filtered as spam by receiving servers, which is why total reply rate drops to near zero.
Key Takeaways
- A domain blacklist (also called a DNSBL or RBL) is a list of domains and IPs that mail servers reference to block or filter suspected spam sources.
- Check both your domain and your sending IP: MXToolbox scans 90+ blacklists in one query, and Google Postmaster Tools shows Gmail-specific reputation.
- Total reply rate is the fastest field signal of a blacklist problem. If replies drop to zero, your email is likely being filtered before a human sees it.
- A warmed mailbox tops out at roughly 30 to 50 sends per day; overloading one mailbox is a common trigger for reputation damage and listings.
- Alchemail manages 100+ sending domains and 200+ sending accounts, and we monitor blacklist status continuously across all of them.
- Delisting takes anywhere from minutes (automated) to weeks (manual review), and it fails if the underlying sending behavior is not fixed first.
What does it mean for a domain to be blacklisted?
A blacklisted domain is one that appears on a DNSBL (Domain Name System Blacklist), a database that receiving mail servers query in real time to decide whether to accept, filter, or reject incoming email. When your domain or sending IP is listed, providers like Gmail and Outlook route your messages to spam or bounce them entirely, which collapses inbox placement and reply rate.
Blacklists exist because receiving servers need a fast way to block known spam sources. There are two things that get listed: your sending IP address and your domain reputation. A shared IP can be listed because of another sender's behavior, while a domain gets listed based on your own content, volume, and complaint signals. You need to check both. For more on the infrastructure layer, see our guide on cold email domain setup.
How do you check if your domain is blacklisted?
To check if your domain is blacklisted, enter your domain and sending IP into a multi-blacklist lookup tool, review Google Postmaster Tools for Gmail reputation, and send a seed-list test to confirm where real messages land. Run all three, because a single tool only covers part of the picture and a clean DNSBL result does not guarantee inbox placement.
Here is the practical sequence:
- Find your sending IP. Check your email service provider or run a header analysis on a sent message to identify the IP your mail actually leaves from.
- Run a DNSBL lookup. Use MXToolbox Blacklist Check or MultiRBL to scan dozens of lists at once for both domain and IP.
- Check Google Postmaster Tools. This shows domain and IP reputation as Gmail sees it, plus spam complaint rates.
- Check Microsoft SNDS if you send to Outlook or Hotmail addresses.
- Run a seed test. Send to a set of test inboxes across Gmail, Outlook, and Yahoo to see actual placement.
Blacklist check tools compared
| Tool | Checks | Best for | Cost |
|---|---|---|---|
| MXToolbox Blacklist Check | Domain + IP across 90+ DNSBLs | Fast broad scan | Free tier |
| MultiRBL.valli.org | IP across 100+ lists | Deep IP-level detail | Free |
| Google Postmaster Tools | Gmail domain + IP reputation | Gmail placement | Free |
| Microsoft SNDS | Outlook/Hotmail IP reputation | Microsoft placement | Free |
| Seed-list test (GlockApps, etc.) | Actual inbox vs spam placement | Real-world confirmation | Paid |
Related reading: our breakdown of email deliverability tools.
Why is total reply rate the clearest signal of a blacklist problem?
Total reply rate is the clearest field signal of a blacklist problem because a reply, even a negative one, is direct proof that your email reached an inbox and a human read it. Total reply rate is the percentage of contacted prospects who reply for any reason. When it drops to near zero across a campaign that was previously working, deliverability, not copy, is the likely cause.
Total reply rate is never a vanity metric. It is the most honest measure of whether email is landing, because it requires a human action that spam-foldered mail almost never produces. Open rate, by contrast, is unreliable: tracking pixels are blocked or pre-fetched by mail clients, and Alchemail runs with open tracking off entirely. If any metric deserves the vanity label, it is open rate.
So when you suspect a blacklist, watch reply rate first. A sudden collapse tells you to run the technical checks above. See how we think about this in reply rate benchmarks.
Why do domains get blacklisted in the first place?
Domains get blacklisted because of sending behavior that looks like spam to receiving servers: high volume from a cold mailbox, spam-trap hits, spikes in complaint rate, missing authentication records, or content that trips filters. Blacklisting is a symptom of an infrastructure or behavior problem, not a random event, which is why fixing the cause matters more than requesting delisting.
The most common triggers we see:
- Overloading a single mailbox. A warmed mailbox tops out at roughly 30 to 50 sends per day at steady state. Pushing hundreds of emails through one account is a fast route to a listing. This ceiling is exactly why Alchemail runs 200+ sending accounts across 100+ domains instead of high volume per mailbox.
- Missing or broken authentication. Absent SPF, DKIM, or DMARC records signal a poorly configured, spammy sender.
- Hitting spam traps. Sending to dead or purchased addresses that exist only to catch spammers.
- High complaint rates. Too many recipients marking messages as spam.
- No warmup. Sending cold volume from a brand-new domain with no reputation history.
Deliverability and infrastructure come before copy. The best cold email in the world cannot rescue mail that lands in spam. For the setup that prevents listings, read our email warmup guide.
How do you get your domain off a blacklist?
To get off a blacklist, first fix the sending behavior that caused the listing, then submit a delisting request through the specific blacklist's removal process. Most DNSBLs publish a lookup page where you enter your domain or IP and request removal. Automated lists delist in minutes once the issue clears; manual-review lists like some Spamhaus entries can take days to weeks.
The order matters. Requesting delisting before you fix the cause gets you relisted almost immediately. Steps:
- Stop sending from the affected domain or IP. Continuing damages reputation further.
- Identify and fix the trigger. Reduce per-mailbox volume to 30 to 50 sends per day, repair authentication, and scrub your list of invalid addresses.
- Warm the mailbox again if reputation is badly damaged.
- Submit the delisting request on each list where you appear.
- Monitor reply rate and reputation for two to four weeks to confirm recovery.
If a domain's reputation is beyond repair, the practical move is often to retire it and route through fresh infrastructure. This is why we spread sending across 100+ domains: no single listing can take down a whole campaign. See how many domains you need.
FAQ
How often should I check if my domain is blacklisted?
Check at least weekly if you run active cold email campaigns, and immediately whenever total reply rate drops sharply. Blacklist status can change overnight based on complaint spikes or spam-trap hits, so a monthly check is too slow for outbound at scale. Teams managing many domains should automate monitoring so listings surface within hours instead of days.
Is a domain blacklist the same as an IP blacklist?
No, they are different but related. A domain blacklist lists your sending domain based on your own content and behavior, while an IP blacklist lists the server address your mail leaves from, which can be shared with other senders. You must check both, because a clean domain on a listed IP still lands in spam.
Can I still send email while my domain is blacklisted?
Technically yes, but you should not. Sending while listed pushes messages into spam folders, generates more complaints, and deepens the reputation damage that caused the listing. Pause sending from the affected domain, fix the root cause, request delisting, and confirm placement with a seed test before resuming. Continuing to send is the fastest way to become permanently damaged.
Does open rate tell me if my domain is blacklisted?
No, open rate is unreliable for this and for deliverability generally. Tracking pixels are blocked or pre-fetched by many mail clients, which inflates or suppresses opens regardless of inbox placement. Alchemail runs with open tracking off entirely. Use total reply rate as your field signal instead, since a reply proves a human saw the message in an inbox.
How long does it take to get delisted from a blacklist?
Delisting takes anywhere from a few minutes to several weeks depending on the list. Automated blacklists remove you within minutes once the triggering behavior stops. Manual-review lists such as certain Spamhaus entries can take days to weeks. Critically, delisting fails and relisting happens fast if you have not fixed the underlying sending problem first.
What tool checks the most blacklists at once?
MXToolbox Blacklist Check and MultiRBL.valli.org each scan the widest range in a single query, with MXToolbox covering 90+ DNSBLs and MultiRBL covering 100+ IP-based lists. Both are free for basic use. Pair either with Google Postmaster Tools for Gmail-specific reputation and a paid seed-list test to confirm actual inbox placement, since DNSBL results alone do not show where mail lands.
Will fixing my domain reputation restore my reply rate?
Fixing reputation restores reply rate only if deliverability was the actual cause of the drop. Once your domain is delisted, authentication is repaired, and per-mailbox volume is back under 50 sends per day, inbox placement recovers over two to four weeks and replies return. If reply rate stays low after placement recovers, the problem is targeting, offer, or copy, not the blacklist.