How to Check If a Domain Is Blacklisted

If your emails are landing in spam or not being delivered, your domain might be blacklisted. Blacklisting occurs when your domain is flagged for spam, phishing, or other suspicious activities. This can severely impact your email deliverability, with inbox placement rates dropping as low as 10–30%. Here's how to check and fix it:

1. Gather Information: Identify your sending domain, IP address, and any tracking or link-shortener domains used in your emails.
2. Use Blacklist Checkers: Tools like MXToolbox, ZeroBounce, or Site24x7 can scan multiple blacklists to see if your domain or IP is flagged.
3. Check Major Blacklists: Verify listings directly on Spamhaus, Barracuda, and SURBL for accurate results.
4. Review DNS Records: Ensure SPF, DKIM, and DMARC records are properly configured to avoid authentication errors.
5. Fix Issues: Address spam complaints, high bounce rates, or compromised servers. Clean your email list and secure your domain.
6. Request Delisting: Submit removal requests to blacklists after resolving the root cause.

Proactive monitoring and proper email setup are key to avoiding blacklists in the future. Tools like Primeforge can simplify DNS configuration and ensure strong email deliverability from the start.

Preparing to Check Your Domain

Before diving into a blacklist check, it's important to gather the right information to get a clear picture of your domain's reputation. Having the right details on hand ensures you’ll uncover actionable insights without missing anything crucial.

What Information You Need

To run an effective blacklist check, you'll need three main pieces of information: your sending domain, your domain's IP address, and any tracking or link-shortener domains tied to your emails.

Your sending domain is the one shown in the "From" field of your emails. Mailbox providers evaluate both your domain and the IP address of the mail server sending your messages. To get a complete reputation overview, you’ll need to verify both. If you're running cold outreach campaigns, you’re probably using tracking domains to monitor email opens and clicks, or custom link shorteners to track engagement. These domains can develop their own blacklist issues separate from your primary domain. Make a list of all domains that appear in your email headers or URLs. This includes your main domain, any CNAME records linked to your email service provider, and any branded or third-party link shorteners.

"For each mailbox you buy with Primeforge, we take care of setting up DMARC, SPF, DKIM, and custom domain tracking, following industry best practices." – Primeforge

Once you've identified your domains, the next step is to locate your domain's IP address.

How to Find Your Domain's IP Address

Finding your domain's IP address is straightforward. If you're comfortable with command-line tools, you can use the following commands:

• On Windows: Open Command Prompt and type ping yourdomain.com.
• On Mac or Linux: Open Terminal and run the same command.

For more detailed DNS information, you can use nslookup yourdomain.com or dig yourdomain.com. For example, running dig mx yourdomain.com will display your domain's MX records, which reference your mail server.

Prefer a simpler, visual method? Many blacklist checker tools, like MXToolbox, Site24x7, or Sitechecker, can automatically pull your domain's IP address when you enter your domain name. These tools eliminate the need for command-line work and provide instant results.

For blacklist checks, you'll need the IP address of your mail server, which is listed in your domain's MX records. If you're unsure about the IP of your outbound mail server, reach out to your email provider for clarification.

Keep in mind that some domains use multiple IPs for redundancy or load balancing. If your setup includes several mail servers, make sure to document each IP. Even one compromised or blacklisted IP can hurt deliverability for all domains on that server.

Setting Up a Baseline for Reputation

Before checking for blacklisting, it’s a good idea to establish a baseline for your domain's reputation. This involves creating a positive sending history and ensuring your technical setup is solid from the start.

Begin by gradually increasing your email volume. Start small - send 20–50 emails per day - and slowly ramp up to show consistent, legitimate sending behavior. Sudden spikes in email volume can set off spam filters, so consistency is key.

Another critical factor is DNS record alignment. Make sure your SPF, DKIM, and DMARC records are properly configured to validate your sending domain. These records play a big role in building trust with mailbox providers.

"Primeforge takes care of all the technical deliverability details - SPF, DKIM, DMARC, domain warm-up, and DNS records - without me needing to touch anything. The mailboxes come pre-configured with US-based IPs, which gives a strong deliverability baseline right out of the gate." – Dominique W.

If you’re using Primeforge, their automated DNS setup simplifies this process. They also integrate with Warmforge, which streamlines domain warming and keeps track of your reputation in real time.

To complete your baseline, record key metrics like your domain age, email sending volume, bounce rate, and complaint rate. Run an initial blacklist check using a tool that scans a wide range of databases. For example, MXToolbox checks over 100 DNSBLs, while ZeroBounce looks at more than 200 email blacklists. Save these results as your starting point. If you notice blacklist issues in the future, you’ll be able to tell whether they’re new or pre-existing problems that need immediate attention.

For ongoing monitoring, tools like Uptime.com can alert you to new blacklist listings quickly. Once your baseline is in place, you’ll be ready to move forward with a blacklist check and protect your email campaigns from deliverability issues.

How to Check If Your Domain Is Blacklisted

Once you have your domain information ready, the next step is to conduct a thorough blacklist check. While the process itself is simple, knowing which tools to use and how to interpret the results is what truly matters.

Using Multi-Blacklist Checkers

Multi-blacklist checkers are a great starting point. These tools scan multiple DNS-based blacklists (DNSBLs) to see if your domain or IP address has been flagged. Tools like MXToolbox, Mailtrap, Site24x7, ZeroBounce, and Smartlead.ai allow you to input your domain or IP address and quickly generate a report. This report will highlight whether your domain is listed, the name of the blacklist, and the reason for the listing (e.g., spamming, phishing, or malware distribution).

Each tool varies in the number of blacklists it checks. For instance:

• MXToolbox scans mail server IPs against over 100 DNS-based email blacklists.
• Site24x7 checks more than 10 popular blacklist databases in real time.
• ZeroBounce offers a free manual checker and a paid service that monitors over 200 email blacklists, complete with automatic notifications.
• Smartlead.ai provides in-depth scans, identifying vulnerabilities, spam issues, and spoofing risks, along with actionable recommendations.

It’s important to check both your domain and sending IP address, as blacklisting can occur at either level, affecting your email deliverability. For setups with multiple mail servers, make sure to check each IP address individually. While these tools are generally dependable, they may occasionally display outdated information. To ensure accuracy, cross-check results directly with the blacklist providers. This initial step lays the groundwork for deeper verification.

Checking Specific High-Impact Blacklists

After using a multi-blacklist checker, confirm your results by visiting major blacklist providers directly. High-impact blacklists like Spamhaus, Barracuda, and SURBL have lookup tools on their websites. For example, if a tool indicates that your domain is listed on Spamhaus, you can verify this on Spamhaus’s official lookup page.

Understanding why your domain was listed is critical. A "spam" designation might point to issues like sending emails to invalid addresses or receiving multiple complaints. On the other hand, labels like "malware" or "phishing" suggest your domain or server may be compromised or hosting harmful content. Addressing each listing individually is important since the causes and solutions may differ. Resolving these issues promptly is essential to protect your email deliverability and maintain your domain's reputation.

Verifying DNS and Authentication Records

Properly configured SPF, DKIM, and DMARC records are key to email authentication and can prevent spoofing attempts. These records not only establish the legitimacy of your emails but also play a significant role in maintaining your domain's reputation and email deliverability.

Misconfigured authentication records can lead to blacklisting and delivery failures. For instance, an SPF record exceeding the 10 DNS query limit can harm email deliverability. Many multi-blacklist tools also include DNS record verification, making it easier to review your setup during the blacklist check.

If you manage your DNS records manually, tools like MXToolbox or DNSChecker can help you ensure your SPF, DKIM, and DMARC records are correctly formatted and published. Look out for syntax errors or missing entries that could weaken your email authentication.

For those managing multiple domains, automated solutions like Primeforge can simplify the process. Primeforge automatically configures DMARC, SPF, DKIM, and custom domain tracking when you purchase a mailbox, following industry best practices. This automation helps prevent errors that could lead to blacklisting or delivery issues.

How to Interpret Blacklist Results

Once you’ve verified your domain’s status, the next step is diving into the details of the blacklist reports. These reports hold the key to understanding what went wrong and how to fix it, which is crucial for maintaining a healthy email infrastructure and keeping your cold outreach efforts on track.

Breaking Down Blacklist Report Details

Blacklist reports typically include essential information like:

• The blacklist provider (e.g., Spamhaus, Barracuda, SURBL, or UCEPROTECT)
• Listing status (active, inactive, or pending)
• Record type (IP, domain, or URL)
• The reason for being listed
• Timestamps showing the last update

Major blacklist providers like Spamhaus are especially influential, as they’re widely referenced by email giants such as Gmail, Outlook, and Yahoo. A listing with them can cause serious inbox placement problems.

The reason for listing is particularly important - it could point to spam complaints, open relay configurations, malware, phishing, or policy violations. This explanation is your starting point for diagnosing and resolving the issue.

Some reports go further, offering severity indicators like "high-impact" or "spam source." These can help you prioritize your response, especially if you’re managing time-sensitive outreach campaigns.

It’s also crucial to understand the difference between major and minor blacklists. A listing on a major blacklist can lead to widespread spam-foldering or even blocked SMTP connections. On the other hand, a listing on a smaller or niche blacklist might only affect a limited group of recipients, with less impact on overall deliverability.

Identifying Domain, IP, and Content Issues

Blacklist reports can help you pinpoint whether the issue lies with your domain, your server’s IP address, or specific URLs in your email content.

• Domain-level issues: These typically involve the sending domain or subdomains used in your From address, Return-Path, or tracking links. They often stem from spam complaints, poor list hygiene, or email authentication errors (e.g., incorrect SPF, DKIM, or DMARC settings). Fixing these issues might involve improving list quality, tightening permissions, and double-checking your DNS and authentication configurations.
• IP-level issues: If your mail server’s IP address is flagged, tools like MXToolbox or Site24x7 can show its status across multiple blacklists. Common causes include high-volume sending, shared server problems, or compromised servers. Solutions might involve pausing email campaigns, switching to cleaner dedicated IPs, or moving to a dedicated infrastructure. Providers like Primeforge offer dedicated U.S.-based IPs and mailboxes through Google Workspace or Microsoft 365 to minimize these risks.
• Content or URL-related issues: Specific URLs in your emails - like those in landing pages or tracking links - might be flagged for phishing, malware, or low-quality content. While you may still be able to send emails, messages containing the flagged URLs could be filtered out. Fixing this often requires cleaning up the affected pages, removing malicious code, and using safe, reputable links. Many teams in the U.S. mitigate these risks by using separate domains for tracking, outreach, and production, ensuring that a single issue doesn’t damage their overall sending reputation.

Gauging Urgency and Risk

The number and type of blacklist listings can give you a clear picture of how severe the problem is. A listing on one or two smaller blacklists might indicate minor or outdated issues that need attention but don’t necessarily require you to halt campaigns. However, even a single listing on a major blacklist - especially one affecting Gmail, Outlook, or corporate email filters - demands immediate action.

If your domain or IP appears on multiple blacklists (e.g., 10 or more), it’s often a sign of deeper problems, such as aggressive unsolicited email campaigns or a compromised server. This could lead to serious consequences like hard bounces or widespread spam-foldering.

To prioritize your response, you can categorize listings into:

• Tier 1 (high-impact): Requires immediate action, such as pausing campaigns or switching IPs.
• Tier 2 (mid-impact): Needs prompt attention but may not halt operations entirely.
• Tier 3 (low-impact): Minor issues that can be addressed over time.

Your DNS and email authentication records also play a critical role in interpreting blacklist results. For instance, a missing or overly permissive SPF record can allow others to misuse your domain, while weak or absent DKIM signatures can reduce trust in your emails. Tools like Primeforge automate the setup of DMARC, SPF, DKIM, and custom domain tracking, ensuring your email environment aligns with industry standards.

What to Do If Your Domain Is Blacklisted

A blacklisted domain can bring your outreach efforts to a standstill. To get back on track, you need to act fast and follow a clear recovery process. Here's how to address the issue and prevent it from happening again.

Finding the Root Cause

Before anything else, pinpoint why your domain was blacklisted. Use multiple blacklist checkers to scan your domain and sending IPs. Then, dig into your SMTP logs, bounce messages, and security reports to uncover the problem. Issues like high spam complaints, unverified email lists, sudden spikes in volume, or authentication misconfigurations are often to blame.

Most blacklist providers offer a "reason for listing" or policy page explaining why your domain was flagged. Common reasons include:

• High spam complaint rates
• Sending to purchased or unverified email lists containing spam traps or invalid addresses
• Sudden increases in email volume that mimic spam behavior
• Compromised mailboxes or API keys being used for unauthorized emails
• Missing or poorly configured email authentication (SPF, DKIM, or DMARC records)

Gather evidence like SMTP logs and bounce reports to understand the issue fully. Bounce messages often include rejection codes pointing to specific blacklists (e.g., "blocked by Spamhaus" or "listed on Barracuda"). Check spam complaint rates from your email service provider or inbox providers like Gmail and Outlook. If you suspect a security breach, run malware scans on your servers and review account login logs, API access, and SMTP credentials for unauthorized activity.

For example, one common scenario involves a sales team using a purchased email list without proper vetting. This can lead to spam trap hits and trigger multiple blacklists. Similarly, a hacked mailbox sending phishing emails can result in immediate blacklisting. In both cases, tracing the evidence - from logs to bounce codes - helps you identify and fix the issue before moving forward.

Fixing Technical and Sending Issues

Once you’ve identified the problem, it’s time to resolve it. Blacklist providers need to see that you’ve addressed the root cause before they’ll remove your domain.

Start with your email authentication. Verify and fix your SPF, DKIM, and DMARC records. Correct any DNS errors, close open relays, and patch security vulnerabilities. If needed, pause high-volume outreach campaigns until your reputation improves.

If the issue involves server security or configuration, remove flagged malware or phishing content. Strengthen account security by enforcing strong passwords, enabling two-factor authentication, and revoking any exposed API tokens or SMTP credentials.

For sending behavior issues, take immediate action:

• Stop or reduce high-volume cold outreach until your reputation recovers.
• Remove invalid, unengaged, and role-based email addresses from your lists.
• Avoid purchased lists - they’re a major source of spam traps and invalid addresses.
• Improve email content by avoiding spammy keywords, misleading subject lines, excessive links, and image-only messages. Always include a clear unsubscribe link.

To protect your primary domain, consider isolating your cold outreach infrastructure. Using the same domain and IPs for both transactional emails (e.g., password resets) and outreach increases the risk of widespread blacklisting. Services like Primeforge offer dedicated Google Workspace and Microsoft 365 mailboxes for cold outreach, with automated DNS setup and US-based IPs. This separation ensures that issues with outreach campaigns don’t affect your main domain or critical emails. Primeforge also simplifies maintaining proper SPF, DKIM, and DMARC records across multiple domains with bulk updates.

Once you’ve addressed these issues, you can move on to requesting delisting.

Requesting Delisting from Blacklists

After fixing the underlying problems, request removal from each blacklist. The process differs between providers, so handle them individually.

Visit each blacklist’s website to review their policies and removal procedures. Some blacklists automatically remove domains after a period of no problematic activity, while others require a manual request through a form or support ticket.

When submitting a delisting request, keep it concise and factual. Include:

• Your domain or IP details
• Contact information
• A summary of the corrective actions you’ve taken

Be ready to provide evidence if requested, such as:

• Sample email headers showing updated SPF, DKIM, and DMARC alignment
• Logs confirming that problematic sending has stopped
• Security scan reports, if relevant
• Metrics showing improvements before and after remediation

Keep in mind that delisting can take hours or even days, depending on the provider’s process. Run blacklist checks regularly - daily at first, then weekly - to monitor progress. Document submission dates, responses, and ticket numbers to stay organized and follow up if needed.

Preventing Future Blacklisting

Getting off a blacklist is only part of the solution. The key is to prevent it from happening again by adopting proactive measures.

Use continuous monitoring services to keep an eye on your domain and IP status. Tools like ZeroBounce monitor over 200 blacklists and send alerts if your domain appears on any of them. Similarly, Uptime.com scans about 100 blacklists daily and notifies you immediately of new listings. These alerts let you act quickly to minimize damage.

Internally, set up dashboards to track metrics like spam complaint rates, bounce rates, and engagement (opens and clicks). Establish thresholds - for example, a bounce rate above 5% or complaint rate above 0.1% - that trigger reviews. Regularly audit your DNS and authentication records, especially after infrastructure changes.

Strengthen security by enforcing strong passwords, enabling two-factor authentication, and limiting API access to essential services. Document your sending policies, including approved list sources, daily send limits, warm-up procedures for new domains, and content guidelines.

For teams managing multiple outreach domains, platforms like Primeforge simplify maintenance. Features like bulk DNS updates ensure consistent SPF, DKIM, and DMARC configurations across all domains. Their multi-domain management tools also allow you to monitor each domain’s reputation separately, rotate domains when needed, and avoid reputation issues before they escalate.

Conclusion

Keeping a close eye on your domain is essential for protecting both your email deliverability and reputation. This involves running thorough blacklist checks, digging into SMTP logs and bounce messages to uncover root causes, resolving technical or sending issues, and submitting detailed delisting requests backed by evidence of corrective actions. More importantly, adopting continuous monitoring helps you spot new issues early, preventing them from disrupting your outreach campaigns.

Shifting from reactive checks to proactive monitoring marks a major step forward for teams focused on maintaining a strong email infrastructure. With specialized monitoring tools, you can address problems in hours rather than days, reducing the risk of sender reputation damage and ensuring your emails consistently land in inboxes.

A reliable email infrastructure is the backbone of blacklist prevention. As your outreach efforts grow, tools like Primeforge offer a streamlined solution. Primeforge provides Google Workspace and Microsoft 365 mailboxes tailored for cold outreach. With automated DNS setup, bulk DNS updates for proper authentication, US-based IPs, and pre-warmed mailboxes, it ensures strong deliverability from the very beginning.

FAQs

What causes a domain to get blacklisted, and how can you prevent it?

Domains often get blacklisted when they're linked to activities like sending spam emails, hosting harmful content, or dealing with security breaches. These problems can seriously damage your domain’s reputation and impact email deliverability.

To keep your domain off blacklists, here are some practical steps:

• Keep an eye on your domain's reputation using tools designed for blacklist monitoring. Regular checks can help you spot issues early.
• Strengthen your domain’s security with proper DNS settings and authentication protocols like SPF, DKIM, and DMARC.
• Steer clear of spammy practices, such as sending unsolicited emails or relying on low-quality email lists.
• Invest in a dependable email infrastructure. Platforms like Primeforge simplify DNS setup and provide tools to maintain strong deliverability.

Taking these steps to actively manage your domain’s health helps ensure smooth performance while safeguarding your online reputation.

How do I set up SPF, DKIM, and DMARC records correctly to avoid being blacklisted?

To keep your domain off blacklists, it's important to correctly set up SPF, DKIM, and DMARC records. These records play a key role in verifying your emails and making sure they meet established standards for email delivery.

Primeforge takes the hassle out of this process by automating the configuration of these records according to recommended practices. This not only shields your domain from spoofing and phishing attacks but also boosts your email reputation and delivery rates.

How can I fix my domain’s reputation and improve email deliverability if it’s blacklisted?

If your domain ends up on a blacklist, the first thing you need to do is figure out which blacklist flagged it. Tools like MXToolbox or MultiRBL can help you pinpoint the issue. Once you know the blacklist, check for the reason behind the listing. Common causes include spam complaints, sending too many emails too quickly, or poor email list management.

To fix this, follow the removal process outlined by the blacklist. Typically, this involves addressing the root problem and submitting a delisting request. While working on this, take steps to improve your email practices. Make sure your DNS settings - like SPF, DKIM, and DMARC - are properly configured. Regularly clean up your email lists and only send emails to people who have given permission. Tools like Primeforge can simplify email infrastructure management by automating DNS setups and providing features to boost deliverability. This can help you maintain a strong sender reputation moving forward.

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• How to Check If Your Domain Is Blacklisted