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DNS Blacklist Check

dns-blacklist-check

Check whether a domain or IP appears on known blocklists used by mail and security systems.

Enter a target and run the tool.

About DNS Blacklist Check

DNS-based blacklists (DNSBLs or RBLs) are real-time reputation databases that mail servers and security gateways query before accepting traffic from a given IP or domain. If your sending IP appears on a major blacklist — Spamhaus, Barracuda, SORBS, SpamCop, and many others — your email gets rejected, deferred, or routed straight to spam, often without any feedback to the sender. A blacklist check resolves your IP or domain against dozens of these reputation feeds at once and reports which (if any) have it listed and why. Our DNS blacklist workflow opens a comprehensive multi-engine query against the value you enter so you can immediately see whether you have a deliverability problem, identify the specific blocklists involved, and follow the delisting procedures each one publishes. This is essential after any deliverability incident, when onboarding a new sending IP from a hosting or ESP provider, when investigating a sudden drop in inbox placement, or as a routine reputation audit for transactional mail infrastructure. Free, opens in a new tab, no signup required.

Common use cases

  • Diagnose why outbound email is being rejected or marked as spam.
  • Verify a new sending IP is clean before launching a campaign.
  • Audit reputation of an existing mail server during a deliverability review.
  • Investigate whether a domain has been flagged by URL or content blocklists.
  • Monitor shared-IP hosting environments for noisy-neighbor reputation damage.

How to use this tool

  1. Enter the IP address or domain you want to check.
  2. Click "Open Blacklist Check" to launch the multi-engine reputation lookup.
  3. Review which blocklists, if any, have the value listed.
  4. For each listing, follow the blocklist's published removal procedure.

Frequently asked questions

Why am I on a blacklist?

Common reasons include sending unsolicited email, unauthenticated mail, compromised accounts, spam traps hit, or shared-hosting neighbors abusing the IP range.

How do I get delisted?

Each blocklist publishes its own removal process — usually requiring you to fix the underlying issue and submit a delisting request via their website.

Are all blacklists important?

Spamhaus, Barracuda, and a few others are widely used and matter most. Many smaller lists carry little weight with major mail providers.

Should I check IP, domain, or both?

Both. IP-level reputation drives initial connection acceptance; domain-level reputation increasingly drives spam-folder placement.