This tool runs on the server.
How it works
The checker verifies whether an IP address or a domain appears on spam blacklists (DNSBL/RBL), the records that many mail servers consult to decide whether to accept or reject a sender's messages.
It queries several lists and shows you which ones report it, which helps diagnose mail delivery problems and know where to request removal. Being on a list usually affects reputation and causes your emails to land in spam or be rejected.
Use cases
- Find out why your emails land in spam or are rejected by other servers.
- Check the reputation of your mail server's IP before a campaign.
- Confirm which lists an IP appears on to request removal on each one.
- Check the reputation of a new IP before putting it to send mail.
Frequently asked questions
What is a DNSBL or RBL?
They are blacklists published through DNS that list IPs or domains associated with spam or abuse. Mail servers consult them at the moment of receiving a message to decide whether to accept, flag, or reject it.
Why did my IP end up on a blacklist?
Common causes are a compromised computer or account sending spam, a misconfigured server, recipient complaints, or sharing an IP with an abusive sender. Each list has its own criteria.
How do I get off a blacklist?
First fix the cause (stop the source of the spam, adjust SPF, DKIM, and DMARC) and then request removal on the site of each list where you appear. Some remove you automatically after a period without incidents.
Does appearing on a list mean my emails will always be rejected?
Not necessarily. Each server decides which lists it consults and how it acts: some reject, others only raise the spam score. Still, being on well-known lists affects deliverability and is worth resolving.