Free tool
Free IP Reputation Check
Check an IPv4 address against major DNS blocklists (DNSBLs) — Spamhaus, SpamCop, Barracuda and SORBS.
About this tool
A free IP reputation checker that queries major public DNS blocklists (DNSBLs) for any IPv4 address. We reverse the IP and look it up against Spamhaus ZEN, SpamCop, Barracuda and SORBS via DNS-over-HTTPS. Any listing usually means mail from that IP will be rejected or scored as spam — you'll see a link to each provider's delisting page.
How to use the Free IP Reputation Check
- Enter the IPv4 address you want to check.
- We reverse the IP and query each blocklist zone in parallel.
- Read the per-list result (listed / clean / unknown).
- If listed, follow the delisting link for each provider to request removal.
Frequently asked questions
- Which blocklists are queried?
- Spamhaus ZEN (zen.spamhaus.org), SpamCop (bl.spamcop.net), Barracuda Reputation Block List (b.barracudacentral.org) and SORBS (dnsbl.sorbs.net).
- What does 'listed' mean?
- The blocklist has flagged this IP as a source of spam or abuse. Receivers using that list will typically block or heavily penalise mail from the IP.
- How do I get delisted?
- Each provider runs its own delisting page (linked in the results). You usually need to fix the underlying issue — compromised account, open relay, weak authentication — before requesting removal.
- Does this support IPv6?
- Not yet. Most consumer blocklists still target IPv4. Enter an IPv4 address (e.g. 203.0.113.10).