Email Blacklist Removal Guide

What Are Email Blacklists?

Email blacklists (also called blocklists or DNSBLs) are real-time databases of IP addresses and domains that have been identified as sources of spam or malicious email. Mailbox providers and spam filters query these lists when processing incoming email. If your sending IP or domain appears on a blacklist, your messages may be rejected or sent to spam.

There are over 300 known blacklists, but not all carry equal weight. A listing on Spamhaus, for example, will have a far greater impact on your deliverability than a listing on a smaller, less widely used list. The key blacklists that most receivers check include Spamhaus (SBL, XBL, PBL), Barracuda BRBL, SORBS, SpamCop, and the CBL (Composite Blocking List).

How Did You Get Blacklisted?

Understanding why you were listed is critical, because you need to fix the root cause before requesting removal. Here are the most common reasons:

1. Sending to Spam Traps

Spam traps are email addresses that should never receive legitimate email. There are two types:

• Pristine traps - Addresses that were never used by a real person. They exist solely to catch senders who scrape addresses from websites or buy lists.
• Recycled traps - Previously valid addresses that were abandoned, deactivated, and then reactivated as traps. Hitting these indicates poor list hygiene (you are sending to people who stopped engaging long ago).

2. High Spam Complaint Rates

When recipients mark your email as spam, the complaint is reported through feedback loops. A sustained complaint rate above 0.1% will attract attention from blacklist operators. If recipients are consistently reporting your email, your IP or domain may be listed.

3. High Bounce Rates

Sending to a large number of invalid addresses (hard bounces) suggests poor list quality. Blacklist operators view high bounce rates as a sign that the sender is not following best practices, which correlates with spam behavior.

4. Compromised Server or Account

If your mail server, website, or email account has been compromised, an attacker may be using your infrastructure to send spam without your knowledge. This is especially common with shared hosting environments and WordPress sites with security vulnerabilities.

5. Shared IP Reputation

If you use a shared IP address (common with shared hosting or budget ESP plans), another sender on the same IP may have triggered the listing. Your email suffers even though you did nothing wrong.

6. Open Relay or Proxy

A misconfigured mail server that allows unauthenticated relaying (an "open relay") will be blacklisted quickly, because spammers actively scan for and exploit open relays.

Checking If You Are Blacklisted

The first step is to determine which blacklists (if any) your domain or IP appears on. Our Blacklist Checker scans the most widely used DNS-based blacklists simultaneously and gives you a clear report showing your status on each list.

To check manually, you can query individual blacklists using DNS. For example, to check if IP 192.0.2.1 is listed on the Spamhaus SBL, reverse the IP octets and query:

nslookup 1.2.0.192.zen.spamhaus.org

If you get a result (typically 127.0.0.x), the IP is listed. If the query fails with NXDOMAIN, you are not listed.

Major Blacklists Explained

Spamhaus

Spamhaus is the most influential blacklist in the world. It operates several lists:

• SBL (Spamhaus Block List) - IPs identified as spam sources. Manual listings by the Spamhaus team.
• XBL (Exploits Block List) - IPs of compromised hosts (botnets, open proxies). Data sourced from the CBL.
• PBL (Policy Block List) - IP ranges that should not be sending email directly (residential IPs, dynamic ranges). Not a "spam" listing per se.
• DBL (Domain Block List) - Domains found in spam messages. Checks the domain in URLs, not the sending IP.

Removal: Visit the Spamhaus Lookup page, enter your IP or domain, and follow the removal instructions for your specific list.

Barracuda (BRBL)

Barracuda Central maintains the Barracuda Reputation Block List. It is widely used by organizations running Barracuda email security appliances. Listings are based on automated spam detection systems.

Removal: Submit a removal request through the Barracuda Central Lookup page. Removal typically takes 12-24 hours if the spam issue has been resolved.

SORBS (Decommissioned)

SORBS (Spam and Open Relay Blocking System) was shut down in mid-2024. The service no longer maintains its blacklists or processes delisting requests. However, some older mail server configurations may still query SORBS lists, so you may still see SORBS appear in blacklist check results.

Removal: No action needed. Since SORBS is no longer maintained, listings will not affect your deliverability with any mail server that has updated its blacklist configuration. If a receiving server is still blocking you based on SORBS, the issue is on their end.

SpamCop

SpamCop is a complaint-driven blacklist. Users report spam through the SpamCop reporting service, and IPs that receive multiple reports are listed. SpamCop listings typically expire automatically within 24-48 hours if no new reports come in.

Removal: Check your status on the SpamCop Blocking List page. Listings are self-expiring. Stop sending spam, and the listing will clear within 1-2 days. You cannot manually request removal.

CBL (Composite Blocking List)

The CBL lists IPs that are sending email as part of botnets or through compromised systems. If your IP is on the CBL, it almost certainly means your server or a machine on your network has been compromised by malware.

Removal: Clean the infection first. Then visit the CBL Lookup page and request removal. CBL provides diagnostic information about the specific malware or exploit they detected.

Blacklist Lookup & Removal Forms

Below are direct links to the official lookup and removal pages for each major blacklist. Bookmark these for quick access when you need to check your status or submit a delisting request:

Step-by-Step Removal Process

Step 1: Identify All Listings

Use our Blacklist Checker to scan all major blacklists. Note every list where you appear.

Step 2: Diagnose the Cause

Review your sending logs, bounce messages, and spam complaints. Look for:

• Unusual spikes in outbound email volume
• Bounce rates above 5%
• Spam complaint rates above 0.1%
• Signs of server compromise (unfamiliar emails in your outbound queue)
• Open relay configuration

Step 3: Fix the Root Cause

Address the underlying issue before requesting removal:

• Remove invalid addresses and spam traps from your lists
• Fix any server misconfigurations (open relays, missing authentication)
• Clean up compromised systems and change all passwords
• Implement proper authentication (SPF, DKIM, DMARC)
• Set up proper bounce handling to automatically remove invalid addresses

Step 4: Request Removal

Visit each blacklist's website and follow their specific delisting procedure. Be honest about what happened and what steps you have taken to prevent recurrence. Most blacklists have an online form or self-service removal tool.

Step 5: Monitor After Removal

After delisting, continue monitoring your status. Some lists re-evaluate periodically, and you could be re-listed if the problem was not fully resolved. Check your blacklist status weekly for the first month after removal.

Preventing Future Listings

Prevention is far easier than remediation. Follow these practices to stay off blacklists:

List Hygiene

• Use double opt-in for all new subscribers
• Remove hard bounces immediately after the first bounce
• Prune inactive subscribers after 6-12 months of no engagement
• Never buy, rent, or scrape email lists
• Regularly run your list through an email verification service

Authentication

• Implement SPF, DKIM, and DMARC on all sending domains
• Use a DMARC policy of quarantine or reject
• Verify authentication regularly using our SPF, DKIM, and DMARC checkers

Sending Practices

• Send only to people who have explicitly opted in
• Include a clear, easy-to-use unsubscribe mechanism in every email
• Honor unsubscribe requests immediately
• Maintain consistent sending volumes and avoid sudden spikes
• Monitor complaint rates through feedback loops

Infrastructure Security

• Keep your mail server software up to date
• Ensure your server is not configured as an open relay
• Use strong passwords and two-factor authentication for all email accounts
• Monitor outbound email queues for suspicious activity
• Set up reverse DNS (PTR records) for all sending IPs

Understanding Blacklist Severity

Not all blacklists carry the same weight. Understanding which listings matter most helps you prioritize your remediation efforts.

High-Impact Blacklists

These blacklists are used by a large number of receiving servers and will significantly impact your deliverability if you are listed:

Medium-Impact Blacklists

These lists are checked by some receiving servers but have a narrower reach:

• SORBS - Was widely known but was decommissioned in 2024. Legacy configurations may still query it, but it is no longer maintained.
• UCEPROTECT - Uses a tiered system (Level 1, 2, 3). Level 1 lists individual IPs; Level 2 and 3 escalate to entire IP ranges and ASNs, which can be controversial.
• Truncate (formerly RATS) - Focuses on systems with known security issues.

Low-Impact Blacklists

Some blacklists are rarely checked by major mailbox providers. A listing on these lists is worth noting but may not require urgent attention. Focus your remediation efforts on the high-impact lists first.

Typical Delisting Timelines

Removal times vary significantly by blacklist. Here is what you can typically expect:

When to Contact Your ESP

If you use an Email Service Provider (ESP) like SendGrid, Mailchimp, Amazon SES, or Postmark, contact them when:

• You are on a shared IP - The listing may be caused by another sender on the same IP. Your ESP can move you to a different IP or investigate the cause.
• The blacklist requires ISP-level intervention - Some blacklists only accept removal requests from the IP owner, which is your ESP in this case.
• You are unsure of the cause - Your ESP has access to sending logs and delivery data that can help diagnose the issue.
• You need a dedicated IP - If shared IP reputation is a recurring problem, ask about upgrading to a dedicated sending IP.
• Your account was suspended - Some ESPs proactively suspend accounts that generate blacklist listings. Contact support to understand the issue and have your account reinstated after fixing the problem.

Most ESPs have a dedicated deliverability or compliance team that handles blacklist issues regularly. They are often familiar with the specific removal procedures for each blacklist and can expedite the process.

What to Do After Removal

Getting delisted is only the first step. To avoid ending up back on a blacklist, take these follow-up actions:

Immediate Actions (First 24-48 Hours)

• Verify the removal by re-checking your status with our Blacklist Checker
• Send a small test batch to confirm improved deliverability
• Review your sending logs for any remaining suspicious activity

Short-Term Actions (First 1-2 Weeks)

• Monitor your blacklist status daily for the first two weeks
• If you cleaned your list, gradually resume sending rather than blasting your full list immediately
• Watch bounce rates and complaint rates closely for any spikes
• Consider temporarily reducing sending volume to rebuild reputation

Long-Term Actions (Ongoing)

• Set up automated blacklist monitoring with weekly checks
• Review and improve your email acquisition practices
• Implement or strengthen email authentication (SPF, DKIM, DMARC)
• Document the incident and your remediation steps for future reference