How to check if your email sending IP address is blacklisted?

 In Email Deliverability

Have you ever wondered about being blacklisted, or even what it means? 

The Internet Service Provider (ISP) checks the sender’s reputation, after it has cleared the SMTP server of the recipient. A sender’s reputation is judged on multiple factors including:

  • Track record: history of sending emails in large volumes
  • Spam Score: how many email recipients have marked the Sender’s emails as Spam?
  • Sending history: how many times has the email bounced?
  • Blacklist history: does the sender’s IP address have previous blacklist history?
  • Email Engagement: How many recipients have opened emails and clicked on links/content within the email?

Let’s explore the steps that you should take if you think you have a problem.

What is an email blacklist?

An email blacklist is a real-time database that checks whether an IP address is sending potential spam email. Such blacklists exist with a goal to reduce email spam in the inbox. Ultimately, they exist to keep the email marketing environment clean.

If your recipients are marking your emails as spam, your IP address might end up on a blacklist. You will need to take immediate steps to be taken off the list. 

You need to closely monitor spam rates, and verify your subscriber’s opt-in status. If there is any doubt about the opt-in validity, you may need to request opt-in again. Second, you need to improve engagement rates on your campaigns. It may be time to refresh your email strategy. 

Check your IP address

Run your domain through blacklisting services to see if you have an issue. Take a look at these popular black lists:

  1. Barracuda Reputation Block List:
    The BRBL is open to public and can be used within reason. You can also
    register on this list by providing the list of IP Addresses of your domain name servers (DNS) that will be sending queries. More information about the Barracuda Reputation Block list is available on the Barracuda Networks website.
  2. Spamhaus: The Spamhaus project is one of the most trusted blacklisting companies providing real-time anti-spam protection for internet networks worldwide. Visit their blacklist removal center to check whether your IP address is listed in the latest Spamhaus blocklists.
  3. Spamcop: SpamCop determines the origin of unwanted email and reports it to relevant Internet Service Providers. To get Spamcop reports for your IP addresses or for checking email deliverability problems, you can check their spam reporting center.
  4. MXToolBox:  MXToolBox has an integrated offering of MX record, DNS, blacklist and SMTP diagnostics. The blacklist check will test a mail server IP address against over 100 DNS based email blacklists (Commonly called Realtime blacklist, DNSBL or RBL). Check your IP on MXToolbox for free!
  5. MultiRBL: MultiRBL is a free multiple DNSBL (DNS Blacklist) lookup tool. MultiRBL does not accept any removal requests. You can check the list for MultiRBL here.
  6. SURBL: SURBLs are lists of web sites that have appeared in unsolicited messages. It is not a list of message senders. SURBL is a second stage filter that works with Spamhaus ( to find about 75% of the other unsolicited messages. Spamhaus can help identify 80 to 90% of unsolicited messages. For more information on this tier-2 email filter, visit
  7. Invaluement:  Invaluement is a compilation of 3 commercial anti-spam blacklists: ivmURI, ivmSIP and ivmSIP/24. This is similar to SURBL and sometimes called a domain blacklist. Invaluement indexes a list of domain names and IP addresses found within hyperlinks in spam emails. For more information, visit

How to remove your IP addresses from a blacklist?

You must submit a delisting request if your IP address has been blacklisted. First, you should change the behavior that caused the delisting. If not, you will likely be delisted again. If your request is denied after the second or third attempt, it will be more difficult to be relisted.


At Pepipost, we know how important your reputation is, so our team will help you to monitor blacklists. Our 24/7 chat team is always ready and willing to help with any questions that you may have related to blacklists.

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