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

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

Posted under Developer , Email Delivery , Transactional Email on April 12, 2018

Once an email is cleared by SMTP Server of recipient, the ISP checks the sender’s reputation. A sender’s reputation is judged on multiple factors including –

– Track record of ESP for sending emails in large volumes

– Spam Score: How many email recipients have marked Sender emails as Spam

– Blacklist history: How many times have the email bounced? Has the sender’s IP address been blacklisted previously?

– Email Engagement: How many recipients have opened emails and clicked on links / content within email. A high degree of engagement (i.e. Open rates and click thru rates) would lead to a healthy reputation score.

One way to improve your email sending reputation is to not be blacklisted.

What is an email blacklist?

An email blacklist is a real-time database that checks whether an IP address is sending email that could be considered spam.  Such blacklists exist with a goal to reduce email spam and keep the email marketing environment clean.

If a lot of recipients are marking your emails as spam, there is a chance that your IP address might end up on a blacklist. It is important that once you discover that you’re on a blacklist, you take the required steps to remove your IP address from that list.

To remove yourself from a blacklist, you need to closely monitor spam rates and improve engagement rates of your campaigns. This can be done by allowing users to opt-in to campaigns and also by sending engaging content in emails that are neatly designed.

How to check if you are IP address is blacklisted?

There are multiple resources out there to check whether your IP is blacklisted. First and foremost, you need to have 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 currently live Spamhaus blocklists.

3. Spamcop: SpamCop determines the origin of unwanted email and reports it to the 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. Unlike most blacklists, SURBL are not 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. Invalument:  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. Invalulument has a list of both domain names and few IPs which are discovered within hyperlinks in the body of spam emails. For more information, visit

How to remove your IP addresses from a blacklist?

If you find that your IP address is blacklisted by one of the many services as listed above, then first and foremost you need to submit a delisting request.  If you request a delisting from a blacklisting service, you need to ensure that you change the behavior that caused the listing. If not, you might be delisted once again. It might get progressively harder to get delisted after the second or third attempt.

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.

Found this blog useful? Please rate us
1 Star2 Stars3 Stars4 Stars5 Stars (2 votes, average: 4.00 out of 5)


Dibya Prakash Sahoo|The Business Guy

Leave a Reply

Notify of

By April 24, 2018

How to Check Your Email Sending Reputation?

It’s no surprise that your Sending Reputation plays an essential role in your email program….

Read More

By January 30, 2017

How to stop spam signups?

With online businesses choosing seamless registration experience over security, the problem of spam signups has…

Read More

By September 11, 2018

The Basics of Webhooks

Webhooks are user-defined HTTP callbacks that are triggered by email events such as a successful…

Read More