BLACKLIST CHECKER
Enter a domain name or IP address to check it against 28+ major email blacklists simultaneously. Results in under 5 seconds — no account required.
Error Checking Blacklists
Common causes:
- Domain does not exist or cannot be resolved via DNS
- Typo in the domain name
- Network connectivity issues
- DNS server timeout
Blacklist Results
| Blacklist | Category | Status |
|---|---|---|
HOW EMAIL BLACKLISTS WORK
An email blacklist (DNSBL — DNS-based Blackhole List) is a database of IP addresses and domains known to send spam. When a mail server receives an email, it queries these lists in real time to decide whether to accept, defer, or reject it.
MailFlagger checks 28+ major DNSBLs simultaneously using standard DNS lookups. Results return in seconds. A single listing on Spamhaus ZEN — used by the majority of enterprise mail servers — can block delivery to millions of recipients instantly.
Checking regularly is the only way to catch listings before they impact your campaigns or transactional email delivery.
Key Blacklists Checked
- // Spamhaus ZEN — Composite list combining SBL, XBL, and PBL. Used by the majority of enterprise mail servers globally.
- // Spamhaus DBL — Domain-specific blacklist that checks URLs and domains embedded in email bodies.
- // Barracuda BRBL — IP reputation list from one of the largest email security vendors. Free removal requests available.
- // SpamCop SCBL — Based on spam reports submitted by end users. Listings expire automatically as reports age out.
- // SORBS SPAM — One of the oldest and largest DNSBLs, covering spam sources, open relays, and dynamic IPs.
- // UCEProtect L1/L2 — IP and ASN-level blocking based on spam volume. L2 can affect entire hosting providers.
- // BlockList.de — Lists IPs that have attacked or probed other servers, including SSH, SMTP, and HTTP attacks.
Frequently Asked Questions — Email Blacklists
- How do I know if my domain is blacklisted?
- Enter your domain name or sending IP into the blacklist checker above. The tool queries 28+ DNSBLs simultaneously and returns the status for each list within seconds. "Listed" results — particularly on Spamhaus, Barracuda, or SpamCop — require immediate action.
- Should I check my domain or my IP address?
- Check both. Domain blacklists (Spamhaus DBL, SURBL/URIBL) flag your sending domain. IP blacklists flag the server IP address that physically sends your email. If you use a shared service like Mailgun, SendGrid, or Postmark, check the specific sending IP assigned to your account.
- How do I get removed from an email blacklist?
- Spamhaus offers self-service removal — typically 24–48 hours. Barracuda has a free removal request form at barracudacentral.org. SpamCop listings expire automatically. First stop the spam activity or clean your list, then submit delisting requests.
- Can I be blacklisted even if I'm not sending spam?
- Yes. Shared IP addresses on cheap hosting can be listed because another tenant is spamming. Compromised accounts can trigger listings quickly. UCEProtect L2 even lists entire ASNs (hosting providers), which can affect you with zero personal fault.