Blacklist checker
A listing on a blocklist can send your mail to spam or get it refused. This checks a domain, and the mail server IP behind it, against lists such as Spamhaus, SURBL and URIBL. The check itself runs on warmerly.com, so this page opens it with your domain filled in.
Checks a domain, and the mail server IP behind it, against Spamhaus, SURBL, URIBL and more.
Big lists like Spamhaus refuse queries that arrive through public DNS resolvers, and they signal it with an answer that looks like a listing. A browser check would get that wrong, so this one runs on our own resolver at warmerly.com/blacklist-checker.
What this checks, and how.
- Enter a domain or an IPv4 address and press Open full check.
- The full check opens on warmerly.com in a new tab and queries the lists from Warmerly's own resolver.
- Big lists such as Spamhaus refuse queries that arrive through public DNS resolvers and signal it with an answer that looks like a listing. A check in the browser would get that wrong, which is why this one does not run on this page.
What an email blocklist is.
A blocklist (also called a blacklist or DNSBL) is a public list of IP addresses and domains that some party has judged to be sources of spam or abuse. Mail servers check it over DNS while they accept a message: they ask whether the sending IP, or a domain in the message, is listed, and the answer can raise the message's spam score or make the server refuse it.
There is no single blacklist. Each list is run by a different organisation with its own rules for who gets listed and how to get removed, and each receiving server chooses which lists to use and how much weight to give them. That is why a listing can hurt delivery to one provider and not another, and why being on one small list is not the same as being on Spamhaus.
| Kind | What it lists | Examples the checker queries |
|---|---|---|
| IP lists | The IP address of the server that connects to deliver your mail | Spamhaus |
| Domain lists | Domains found in the sender address or in links inside the message body | SURBL, URIBL |
Your own mail can be affected by either. A message sent through a clean server can still be marked if it links to a listed domain, and a clean domain can suffer if the server it sends through shares an address with a listed sender.
How to read a listing.
A result shows each list that was queried and whether the domain or IP was listed. Treat it as a pointer to look closer, not a verdict. Three things are worth working out first.
- Which list. Some lists are widely used by large providers and a listing there needs fast attention. Others are small or niche and few receivers consult them. Read the list's own page to see who uses it and why it lists.
- What was listed. A listed IP points at the server or provider you send from. A listed domain points at your own domain or at a domain you link to.
- Why. Most lists give a reason or a sample. It might be a compromised account, a sudden jump in volume, mail to addresses that do not exist, or spam-trap hits from an old list.
One thing can mislead you. Large lists such as Spamhaus refuse queries that arrive through public DNS resolvers, and the refusal comes back as an answer that looks like a listing. A check run in a browser through a public resolver can therefore report a listing that does not exist. This is why the check on this page runs on warmerly.com with its own resolver, and why you should be cautious about results from tools that query through a public resolver.
Why senders get listed, and what to do.
| Cause | How to confirm | Fix |
|---|---|---|
| A compromised mailbox or app password | Look for sent mail you did not write, or logins from places you do not use | Change the password, revoke app passwords, turn on two-step sign-in, then request removal |
| A bought or old list | Bounce rate and unknown-user errors are high on the first sends | Stop sending to the list, remove addresses that bounce, and send only to people who have a reason to expect your mail |
| A sudden volume jump | Sending rose sharply from a new or lightly used mailbox | Return to a gradual ramp and warm the mailbox first |
| A shared IP with a bad neighbour | The IP is listed but your own sending is low and clean | Ask your provider, or move to an address with a cleaner history |
| A link to a listed domain | A domain list flags the message but the IP is clean | Remove or replace the link, including tracking and shortener domains |
Getting removed
Each list publishes its own removal process. Fix the cause first. Most lists will not remove an address while the problem is still happening, and some re-list quickly if it comes back. Then follow the list's own steps, which often means a form on the list's website. Do not pay anyone who offers to remove a listing for a fee until you have read the list's own page: removal on the lists named here is handled by the list.
If you send from a hosted mailbox
If your mailboxes sit on a large provider, the sending IP belongs to that provider and a listing there is usually theirs to handle, not yours. Your own domain is the part you control, so check the domain lists first and your authentication second. If you run your own mail server or a dedicated IP, the whole reputation of that address is yours, which is also why a new address needs a gradual start and not a full-volume first day.
Prevention
Authentication helps: a domain with correct SPF, DKIM and DMARC is harder to spoof, and spoofed mail is a common route to a listing. A gradual warmup helps too, because a new mailbox that jumps to full volume looks like a spam run. Check your records with the SPF checker, DKIM checker and DMARC checker, and read the deliverability checker results for the whole domain.
Quick answers.
Why does this open another page?
Public DNS resolvers get refusals from the large lists, and the refusal looks like a listing. The real check needs a resolver of our own, so it runs on warmerly.com.
What if I am listed?
Each list publishes its own removal process. Fix the cause first, such as a compromised account or a bad sending pattern, then follow the list's own steps.
How do I check if my domain or IP is blacklisted?
Enter the domain, or the IP address of the server you send from, into the checker. It queries lists such as Spamhaus, SURBL and URIBL from Warmerly's own resolver and shows each result. Treat a listing as a pointer to investigate, because lists differ in who uses them and why they list.
Does a blacklist listing mean my emails go to spam?
Not always. Each receiving server picks its own lists and decides how much weight to give them. A listing on a widely used list can affect many providers, while a listing on a small list may affect few. Check which list it is and read why it listed you.
How long does it take to get delisted?
It depends on the list. Each one publishes its own removal process and some expire listings by themselves after a period without abuse. Fix the cause first, because lists often re-list a sender whose problem has not stopped.
Can warming up a mailbox get it off a blacklist?
No. Warmup builds a sending history for a clean mailbox; it does not remove a listing. If you are listed, fix the cause and follow the list's removal steps, then warm up and ramp volume gradually afterwards.
Fixed the records? Now warm the mailbox.
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