IP blacklists are databases of addresses flagged for spam, malware, or abuse. If your emails land in spam, websites show CAPTCHAs constantly, or your server gets rejected, a blacklist entry could be the cause. Here's how to confirm, and what you can do.

Step 1: Know your public IP

Start with our IP checker to confirm the exact public IP being checked. If you're on mobile or behind CG-NAT, the IP shown is shared with many users — which is often why it ends up listed through no fault of yours.

Step 2: Run a multi-RBL check

The big blacklists (Spamhaus, SORBS, Barracuda, SpamCop, UCEPROTECT) each have their own lists. Aggregator tools check dozens at once:

• MXToolbox Blacklist Check — free, checks ~90 lists
• dnsbl.info — checks ~60 lists

Step 3: Identify the listing reason

Each blacklist's detail page explains why you're listed — spam reports, open relay, policy-block (dynamic residential range), or malware beacon. Policy listings are the most common for home users: your ISP's dynamic range is pre-blocked for outbound mail, which is actually normal.

Step 4: Get delisted

Each blacklist has a self-service delist form. Remediate first (fix the mail server, patch the infection, move to a business ISP for outbound mail), then submit. Most delistings process within 24–72 hours. Repeat listings lock you out longer.

If you're behind CG-NAT or on mobile

You probably can't get your IP delisted — you don't own it. Your practical options: switch to mobile data if you're on Wi-Fi (or vice versa), reboot your router to request a new IP, or use a reputable VPN whose IPs aren't on the spam lists.

Try it now

Curious what your IP is showing the world right now? Check your IP address & location instantly with our free tool — no signup, nothing stored. Or trace any other IP to see its geolocation, ISP, and network details.