A sudden increase in undelivered emails can indicate a more serious problem than a few invalid addresses. If your messages are being rejected, arriving late, or increasingly landing in spam, the domain or IP address you send from may have been added to a blacklist.
However, appearing on a blacklist does not automatically mean that it is causing your deliverability problems. First, you need to determine which lists contain your domain or IP address, why it was added, and whether that particular blacklist is actually affecting your email delivery. Only after addressing the underlying cause should you begin the removal process.
In this guide, we will walk through the entire process step by step, from checking and diagnosing the issue to blacklist removal and ongoing sender reputation monitoring.
Key Takeaway:
Check your domain and the IP address you actually use to send emails against several reliable blacklist databases to determine whether they are listed and why. If you find an issue, fix the underlying cause first, then follow the official removal procedure for the relevant blacklist. Finally, confirm that your domain or IP address has been removed and continue monitoring your sender reputation and email deliverability.
What Does It Mean When a Domain or IP Address Is Blacklisted?
When a domain or IP address is blacklisted, it means that the operator of that list has identified it as a potential source of spam, malicious activity, or other unwanted email behavior. Email providers may use this information as one of the signals when deciding whether to accept, filter, or reject a message.
You may also see these lists referred to as blocklists, DNSBLs, or RBLs. However, there is no single universal database. Different operators maintain their own lists, apply different criteria, and monitor different types of risky behavior. As a result, appearing on one blacklist does not automatically mean that your emails will be blocked by every provider.
It also matters what exactly has been blacklisted. If it is an IP address, the cause is usually related to the infrastructure used to send the messages. If the domain is affected, the problem may be related to its reputation, how it is used in emails, or the content of the messages. This is why you should check both the sending IP address and the domain when troubleshooting email deliverability issues.
Being listed also does not necessarily mean that your entire email system has been compromised. Before taking action, determine what exactly has been listed, which blacklist reported it, and whether this matches the deliverability problems you are experiencing. Only then can you identify the actual cause and the steps needed to resolve it.
Why Do Domains and IP Addresses Get Blacklisted?
A domain or IP address is usually blacklisted when unwanted or risky activity is detected. The most common reasons include:
- Spam and recipient complaints: Sending unsolicited messages and having emails frequently marked as spam can quickly damage your sender reputation.
- Spam traps and poorly maintained lists: Sending emails to inactive, recycled, or specially created spam-trap addresses is a serious warning signal.
- Compromised accounts or websites: Stolen credentials, a hacked website, or a malicious script can be used to send spam without the owner's knowledge.
- Incorrect mail server configuration: An open relay, for example, can allow third parties to send messages through your server and damage the reputation of its IP address.
- Poor shared IP reputation: When using shared infrastructure, the actions of other users can also affect your email deliverability.
- Phishing and malicious activity: Domains and IP addresses associated with phishing, malware, or other threats may be added to specialized blacklists.
How to Check If Your Domain or IP Address Is Blacklisted
Check both your domain and the IP address actually used to send your emails. They can appear on different blacklists, so checking only one may give you an incomplete picture.
Find the IP Address You Actually Send From
Your website's IP address is not always the same IP address used for outgoing email. If you use Google Workspace, Microsoft 365, a hosting provider, or an SMTP service, your emails may be sent through their infrastructure. You can identify the sending IP address from the headers of a received email. In Gmail, for example, open Show original. If you manage your own mail server, check its configuration or logs.
Check the Domain and IP Address Against Blacklists
Use reliable tools such as Spamhaus and MXToolbox to check your domain and sending IP address. It is a good idea to check more than one service because blacklist operators use different criteria and maintain separate databases.
If you find a listing, focus on which blacklist contains your domain or IP and the reason given for the listing, rather than simply counting how many lists you appear on. Being blacklisted does not automatically mean that every email provider will block your messages, but the reason for the listing can help you determine what needs to be fixed before requesting removal.
How to Remove a Domain or IP Address From a Blacklist
Blacklist removal starts with fixing the reason you were listed in the first place. If the underlying problem remains active, your domain or IP address can quickly be blacklisted again.
1. Identify the Blacklist and the Reason
Determine which list contains your domain or IP address and why it was added. Review any diagnostic information and instructions provided by the operator before taking action. Not every blacklist has the same impact on email deliverability.
2. Fix the Cause of the Listing
The necessary action depends on the specific problem. In most cases, you should:
- secure compromised accounts and change login credentials;
- remove malware, malicious scripts, or other sources of spam;
- fix open relay and other mail server configuration problems;
- remove invalid and unwanted recipients from your email lists;
- check SPF, DKIM, and DMARC if the issue is related to email authentication;
- contact your hosting or email provider if the affected IP address is managed by them.
3. Follow the Official Removal Procedure
Every blacklist has its own removal process. Spamhaus, for example, provides instructions through its IP & Domain Reputation Checker, with the required steps depending on the specific list. If the affected IP address is managed by a provider, they may need to submit the removal request on your behalf.
Microsoft also provides an Anti-Spam IP Delist Portal for certain blocked IP addresses. Always follow the official instructions provided by the relevant operator and avoid third-party services that claim they can bypass the removal process.
4. Confirm That You Have Been Removed
Check the same blacklist again after completing the removal process. If the listing is still active, review its status and the operator's instructions before submitting another request. Keep in mind that removal from one blacklist does not automatically remove you from others.
5. Monitor Email Deliverability
After removal, monitor bounced messages, spam complaints, and delivery errors. If problems continue, investigate your sender reputation and the policies of the specific email provider. Having no active blacklist listing does not automatically guarantee good email deliverability.
How to Tell If a Blacklist Is Actually Causing the Problem
Appearing on a blacklist does not necessarily mean that it is responsible for your deliverability problems. To determine whether there is a connection, check:
- Which blacklist has listed you? Some lists are used much more widely than others.
- What has been blocked? Determine whether the sending IP address, domain, or both are affected.
- What is the reason? The listing may point to spam, a compromised account, malware, or an incorrect configuration.
- What does the delivery error say? A non-delivery report (NDR) often provides information about why the receiving server rejected the message.
If you are blacklisted but your emails are being delivered normally, the receiving providers may not use that particular list. Conversely, if you are not blacklisted but your messages are landing in spam, the problem may be related to sender reputation, email authentication, or other filtering systems.
Blacklist removal therefore makes sense only after you have established that the listing is connected to the problem you are experiencing.
How Long Does Blacklist Removal Take?
There is no standard timeframe. Some listings are removed automatically after the underlying issue has been resolved, while others require a manual request. The process may also take longer if the affected IP address is managed by your hosting, email, or network provider.
For example, once removal from the Spamhaus Domain Blocklist has been approved, the change is processed immediately, although it may take up to 24 hours to be reflected in some local systems. The best approach is to fix the underlying cause first, follow the official removal procedure, and then check whether the listing has been cleared.
How to Prevent Your Domain or IP Address From Being Blacklisted Again
After removal, it is important to protect the reputation of your domain and IP address and prevent the problem from recurring. To reduce the risk:
- Set up email authentication: Configure SPF, DKIM, and DMARC correctly to authenticate legitimate sending sources.
- Keep your email lists clean: Remove invalid addresses and monitor bounced messages and spam complaints.
- Secure your accounts and servers: Use strong passwords, keep software up to date, and monitor for unusual activity.
- Check your DNS configuration: Make sure the necessary DNS records, including reverse DNS where applicable, are configured correctly.
- Monitor your sender reputation: Watch delivery errors and other signs that your reputation may be deteriorating.
- Monitor shared IP addresses: If other users on the same IP address are causing problems, contact your hosting or email provider.
Conclusion
Being blacklisted does not necessarily pose a serious or permanent threat to your email communication. What matters most is identifying the cause early and fixing it rather than focusing solely on getting the listing removed.
Proper email authentication, secure infrastructure, and regular sender reputation monitoring significantly reduce the risk of the problem recurring. By watching for early signs of declining deliverability, you can take action before they begin to seriously affect communication with your customers.
At Jump.bg, we know that the correct configuration of DNS and domain nameserver settings is crucial for the reliable operation of your website and email services. You can register a new domain or transfer an existing one with us, and our team is available to assist you with setting up your domain and hosting services whenever needed.
You can contact us at 02 428 8888 or support@jump.bg.
