Does a blacklist listing mean email will fail?

No. A listing is a signal, not a verdict — different mail providers use different lists alongside their own reputation systems. Mail from a listed IP may still be delivered, and mail from a clear IP can still land in junk.

What should I do if my IP is listed?

First find and fix the cause — often a compromised account, device or misconfigured server. Then follow the delisting process on the blacklist operator's own website; most lists remove entries once the underlying problem stops.

Can I check a domain instead of an IP?

This checker currently takes an IPv4 address, which is what most DNS blacklists track. To find the IPs behind a domain's mail, look up its MX and A records with the Education Host DNS checker first.

Does Education Host store blacklist checks?

This tool runs your check for the current request and does not store it in a database. Normal server and security logs may record requests like any other website.

Why do different blacklist checkers show different results?

Checkers query different sets of lists, and some lists rate-limit or block queries from certain resolvers. Listings also change constantly, so results can differ between tools and over time.

Tools

Blacklist Checker

Check whether an IP address appears on common DNS-based email blacklists.

This checker queries a curated set of DNS blacklists (DNSBLs) using the same DNS-based method mail servers use, and shows whether the address appears on each list. It checks public IPv4 addresses — typically your mail server or hosting IP.

Education Host runs your lookup for this request only. It is not stored in a database by this tool, although normal server and security logs may record requests like any other website.

The basics

What is an email blacklist?

An email blacklist (also called a DNSBL or RBL) is a published list of IP addresses reported for sending spam or showing suspicious behaviour. Mail providers can consult these lists when deciding whether to accept, junk or reject a message.

Blacklists are queried over DNS: a mail server reverses the IP address and looks it up under the list's zone. This checker does exactly the same, against a curated set of lists that is reviewed over time.

Common reasons an IP gets listed

Spam complaints from recipients
A compromised account, device or website sending bulk mail
Open relays or misconfigured mail servers
Shared IP reputation on shared hosting
Dynamic or residential IP ranges, which some lists include by default

Practical uses

When is this tool useful?

Investigating delivery problems

Check the sending IP when messages start bouncing or landing in junk folders.

Checking a new mail server IP

Confirm a newly assigned address starts with a clean reputation before you rely on it.

Monitoring shared hosting reputation

On shared hosting, other tenants' behaviour can affect the IP your mail leaves from.

Preparing a mail migration

Check the reputation of the target IP before moving mail flow to it.

Supporting deliverability conversations

Bring concrete listing information to conversations with hosting or email providers.

If you are listed

What to do if an IP is listed

A listing is a prompt to investigate, not a catastrophe. Find and fix the cause first — delisting requests made while the underlying problem continues are usually short-lived.

1Work out why the address was listed — common causes are a compromised account or device, a vulnerable website script, or a misconfigured server
2Fix the root cause and confirm the unwanted mail flow has stopped
3Visit the blacklist operator's own website — each list documents why an address is listed and how delisting works
4Request delisting once the problem is resolved; many lists also expire entries automatically
5Re-check over the following days and keep an eye on bounce messages

More tools

Related tools

Part of a growing set of free Education Host checks — with more on the way.

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