Security tools

IP Reputation Checker

Check any IPv4 address against 8 major DNS blacklists simultaneously. Find out if your IP is listed and why email may be getting rejected.

Spamhaus ZEN SpamCop SORBS UCEProtect Barracuda PSBL DroneBL Backscatterer

Get started free Sign in

Free · No credit card · 50 credits/day

The 8 blacklists we check

Listed by coverage and industry impact.

Blacklist	Operator	Focus	Impact
Spamhaus ZEN	Spamhaus	Spam senders, botnets, hijacked IPs	★★★★★ Most widely used
SpamCop	Cisco	Spam sources reported by users	★★★★☆ Major providers
SORBS	Proofpoint	Spam, open relays, proxies	★★★☆☆ Corporate filters
UCEProtect L1	UCEProtect	Direct spam senders	★★★☆☆ Some ISPs
Barracuda	Barracuda	Spam, malware, phishing	★★★★☆ Corporate email
PSBL	SURRIEL	Permissive spam blacklist	★★☆☆☆ Moderate use
DroneBL	DroneBL	Botnets, DDoS, abusive IPs	★★★☆☆ IRC, hosting
Backscatterer	UCEPROTECT	Backscatter / bounce spam sources	★★☆☆☆ Targeted

Common reasons for being listed

📨

Spam complaints

Users marked email from your IP as spam. Even opt-in emails can generate complaints if recipients forget signing up or the unsubscribe link is buried.

🤖

Botnet infection

A compromised server or device on your network sent spam automatically. This is common with hacked WordPress sites and misconfigured mail servers.

🔄

Shared IP history

Dynamic or shared IPs are reassigned between customers. You may have inherited a listing from a previous user who abused the IP.

📬

Open relay / proxy

Your mail server was configured to forward email for any sender (open relay), or your server was acting as an open proxy that spammers exploited.

💥

Backscatter

Your server sent bounce messages (NDRs) to forged sender addresses in spam — called backscatter. Backscatterer.org lists IPs that do this.

🔓

Credential stuffing / brute force

Your IP was flagged for automated login attempts against other services — common with VPS IPs that get reported to DroneBL.

How to get delisted

Fix the root cause: Identify and stop the abuse — patch the compromised app, secure the mail server, remove the malware. A delisting without fixing root cause will result in re-listing.

Spamhaus: Submit a removal request at spamhaus.org/lookup. They require you to explain the issue and fix it first.

Barracuda: Self-service removal at barracudacentral.org/rbl/removal-request — usually instant once fixed.

SpamCop / SORBS: Listings typically auto-expire after 30–90 days with no new reports. You can also contact them directly.

UCEProtect: Paid express removal is available. Free removal happens automatically after about 7 days if abuse stops.

Frequently asked questions

Why is my IP on a blacklist?

Common reasons: your IP was previously used to send spam, your mail server was misconfigured and sent unsolicited email, your IP was part of a botnet, or a previous tenant of a shared or dynamic IP had a poor reputation.

How do I get my IP removed from a blacklist?

Each blacklist has its own removal process. Spamhaus requires you to fix the abuse source then submit a removal request. Barracuda offers self-service removal. SORBS and SpamCop listings typically expire automatically after 30–90 days if no new abuse is detected.

Will being on a blacklist affect email delivery?

Yes — major email providers check Spamhaus and SpamCop before accepting email. A Spamhaus ZEN listing will cause most email to bounce or be rejected. Not all blacklists have the same impact — Spamhaus has the broadest coverage.

What is a DNSBL?

A DNSBL (DNS-based Blackhole List) is a database of IP addresses reported as sources of spam, malware or abuse. Mail servers query DNSBLs via DNS lookups — the reversed IP is prepended to the DNSBL domain and if a DNS A record is returned, the IP is listed. The check takes milliseconds and happens before an email is processed.

Related tools

More tools to audit mail and network infrastructure.

DNS Lookup

Query MX and TXT records to verify SPF, DKIM and DMARC setup.

Security Headers Checker

Audit HTTP security headers — HSTS, CSP, X-Frame-Options and more.

WHOIS Lookup

Query domain registration data — registrar, expiry and nameservers.

Check your IP reputation now

Free account. 50 credits per day. Access to 75+ tools instantly.

Create free account →