What this tool checks
- DNS blacklists (Spamhaus ZEN, SpamCop, PSBL, UCEPROTECT…)
- ASN and network owner
- Country and IP block
- Reverse DNS (PTR)
- Abuse contact address
- Abuse report history (when configured)
How to use it
- 01
Enter an IPv4 or IPv6 address, or a domain (its first IP is used).
- 02
Press Check.
- 03
If you're listed, fix the cause first, then follow the delisting process on the list's own site.
Technical details
Blacklist queries
DNS-based blacklists are queried with the IP address reversed. Some lists refuse queries from busy or public resolvers; then the result shows as “Unavailable”.
ASN data
ASN and prefix come from Team Cymru's IP-to-ASN service; network and abuse contact from the regional internet registries' RDAP services.
PTR record
For mail servers, having a PTR record that matches the server name matters for deliverability. Large providers often reject mail from servers without one.
Frequently asked questions
My IP is blacklisted — will my email be affected?
On widely used lists such as Spamhaus, very likely. Fix the cause first (compromised account, open relay, malware), then request delisting.
What does “Unavailable” mean?
The list didn't answer or refused our query. It does not mean your IP is listed.
Why is a dynamic home IP listed?
Some lists (for example Spamhaus PBL) list residential and mobile ranges as addresses that shouldn't send mail directly. It's a policy list, not an accusation.
Why can't I see abuse reports?
Report history requires a third-party service key. Without it, the network's official abuse contact is shown.