IP Address Blacklisted? Here's How to Fix It

One day everything works fine. The next, your emails bounce, websites block you, and online services treat you like a suspect. If this sounds familiar, your IP address may have landed on a blacklist.

IP blacklisting is a common internet security mechanism, but it can catch innocent users in its net. Whether your IP was blacklisted due to someone else's behavior, a compromised device on your network, or a false positive, you can fix it.

What Is an IP Blacklist?

An IP blacklist (also called a DNSBL, blocklist, or Real-time Blackhole List) is a database of IP addresses identified as sources of spam, malware, hacking attempts, or other abusive behavior. Email servers, websites, and security services consult these lists to decide whether to accept or reject connections.

There are hundreds of blacklists operated by different organizations. Some major ones include:

• Spamhaus (SBL, XBL, PBL) — the most widely used email blacklist
• Barracuda Reputation Block List — popular with enterprise email servers
• SORBS — Spam and Open Relay Blocking System
• SpamCop — focuses on user-reported spam sources
• CBL (Composite Blocking List) — detects IP addresses showing botnet-like behavior
• UCEPROTECT — multi-level blacklist (IP, subnet, ASN)

How to Check If Your IP Is Blacklisted

First, find your current IP address using our My IP Address tool. Then use our Blacklist Check tool to scan your IP against dozens of major blacklists simultaneously.

You can also check manually at these sites:

• Spamhaus: lookup.spamhaus.org
• MXToolbox: mxtoolbox.com/blacklists.aspx
• MultiRBL: multirbl.valli.org

If you are running a mail server, check your sending IP regularly — even a brief blacklisting can cause hundreds of bounced emails.

Why Your IP Got Blacklisted

1. Spam Sent from Your Network

The most common reason. This does not necessarily mean you sent spam intentionally. Possible causes:

• A device on your network is infected with malware that sends spam in the background
• Your email account was compromised and used to send bulk messages
• Someone on your shared hosting or VPS was sending spam, and the entire IP got flagged
• Your email server has an open relay configuration

2. Malware or Botnet Activity

If a computer on your network is part of a botnet, it may be sending attack traffic, participating in DDoS attacks, or distributing malware. Security services detect this pattern and blacklist the IP.

3. Previous IP Holder

If you have a dynamic IP address (most residential users do), you may have inherited an IP that was blacklisted by its previous user. ISPs recycle IP addresses, and the new holder gets whatever reputation the old holder left behind.

4. Port Scanning or Brute Force Attempts

If a device on your network is scanning for open ports or attempting brute-force logins on external servers, intrusion detection systems will flag and blacklist your IP.

5. Shared Hosting

On shared web hosting, dozens of websites share a single IP. If one site sends spam or hosts malware, every site on that IP suffers. Check which sites share your IP with a Reverse DNS lookup.

Step-by-Step: How to Get Delisted

Step 1: Identify the Problem

Before requesting removal, you must fix whatever caused the listing. Blacklist operators will reject removal requests or re-list you immediately if the underlying issue is not resolved.

• Run a full malware scan on every device on your network
• Check your email accounts for unauthorized access (look for sent messages you did not write)
• Review your router logs for unusual outbound traffic
• Check for open relays if you run a mail server
• Update firmware and software on all network devices

Step 2: Check Which Blacklists You Are On

Use our Blacklist Check tool to get a complete picture. Note the name of each blacklist that flags your IP — you will need to request removal from each one individually.

Step 3: Request Removal

Each blacklist has its own removal process:

Spamhaus:

• Visit the Spamhaus lookup page, enter your IP
• Click the removal link provided in the listing details
• Fill out the removal request form explaining what you fixed
• Spamhaus typically processes requests within 24 hours

Barracuda:

• Visit barracudacentral.org/lookups
• Enter your IP and request removal
• Usually processed within 12-24 hours

SpamCop:

• SpamCop listings expire automatically after 24-48 hours if no new spam is reported
• No manual removal process

SORBS:

• Visit sorbs.net and use their lookup tool
• Some zones require a removal fee or a waiting period
• Dynamic IP listings can be removed by proving you use a smarthost

CBL:

• Visit abuseat.org
• Enter your IP and click the removal link
• Removal is usually instant, but your IP will be re-listed if the problem recurs

Step 4: Verify Removal

After requesting delisting, wait the specified processing time and then re-check using our Blacklist Check tool. Some lists take hours, others take days.

Step 5: Prevent Re-Listing

• Keep all devices updated and protected with security software
• Use strong, unique passwords for all email accounts
• Monitor your IP reputation regularly
• Set up SPF, DKIM, and DMARC records for your email domain
• If you run a mail server, ensure it is not configured as an open relay

What If You Cannot Get Delisted?

If removal requests are denied or the blacklist is unresponsive, you have a few options:

Get a New IP Address

Ask your ISP for a new IP address. For residential connections, restarting your router may give you a new dynamic IP. For business connections, your ISP can assign a new static IP. Check our guide on how to change your IP address for detailed instructions.

Use a VPN for Browsing

If the blacklisting only affects browsing (some websites blocking your IP), a VPN will mask your blacklisted IP. NordVPN gives you thousands of clean IPs to choose from.

Use a Relay Service for Email

Services like Google Workspace, Microsoft 365, or Mailgun send email through their own infrastructure, bypassing your blacklisted IP entirely. This is often the best long-term solution for email deliverability.

Preventing Future Blacklisting

Prevention is much easier than remediation:

1. Monitor proactively — check your IP against blacklists weekly using our Blacklist Check tool
2. Secure your network — keep firmware updated, use strong passwords, segment IoT devices
3. Use email authentication — implement SPF, DKIM, and DMARC
4. Monitor outbound traffic — unusual spikes in email volume or network traffic are red flags
5. Check your HTTP headers — our HTTP Headers tool can help verify your server configuration

Conclusion

An IP blacklisting is frustrating but usually fixable. The key is to address the root cause first, then request removal. Most blacklists are designed to be responsive to legitimate removal requests once the underlying problem is resolved.

Check your status now with our Blacklist Check tool, and make regular monitoring part of your network maintenance routine.