What is IP Address Blacklisting?

An IP address blacklisted is an undesirable situation for any internet administrator to be in. The effects are far reaching and so have been the solutions created to combat this global plague. But why are IP address blacklisted? What are the effects? How can you prevent this with a trusted hosting company and SSL certificate? And how do you get off the blacklist? These are all anxious questions for which information will be provided to answer them.

Is your IP Address Blacklisted? What is that?

IP address blacklisting helps to identify an illegitimate or malicious IP address. There are tons of blacklisted IP addresses or domains known for spamming or other malicious activities. These lists are widely known as Domain Name System Blacklists DNSBL’s or DNS Blacklists. In fact, the technology behind this method will reject or flag messages that have been sent from a blacklisted IP. While this method is good for many of the protection advantages it offers hosting companies and individuals, it can also be a terrible experience for innocent users of the internet.

Effects of an IP Address Blacklisted

Understanding the effects or symptoms of an IP address blacklisted will give you a keen eye to quickly identify this happening. Can you imagine how great the fall out between your business operations and customers would be with your IP address blacklisted? Well, imagine the chaos under the following circumstances:

  • All communications coming from your IP address bounces – This is a major indicator for Blacklisted IPs. For a company relying greatly on email marketing to a high volume of customers, this can be terrifying as it reduces your effectiveness.
  • All communications coming from your IP address is sent as a spam – This is another major indicator. No one likes spam messages and we often ignore or report them.
  • The DNSBL’s causes loss of revenue with a website or email being down.

6 Reasons for an IP Address Blacklisted

Greater knowledge of what causes this situation can help you understand and rectify it when this happens. DNSBLs operates within its own rules and focuses on abuse categories. The popular abuse among them all is spam. However, there are blacklists that looks at hacking, malware, botnets or even Tpr Exit Nodes. Here are the reasons with further explanation:

  1. Malicious IP addresses – IPs having a historical record of use in cyber attacks.
  2. Proxies that are Anonymous – IPs’ information hidden by proxy servers.
  3. TOR networks – Attackers can use resource on sharing user networks to disguise the source of traffic.
  4. Phishing URLs – Emails sent to innocent account holders for the purpose of phishing attacks
  5. Best Practices Rule Avoided By Email Marketers – Non adherence to email marketing best practicing rules such as having “Unsubscribe links on emails” or ensuring that all recipients have signed up using a “Confirmed Opt-in Process.”
  6. Multiple Failed Login – A high number of failed login attempts to your control panel and email may also result in your issues for you.

How to Fix an IP Address Blacklisted

It is possible to get off a blacklist for most DNSBL within 24 hours. This happens when the IP address operator confirms a solution to the problem. The criteria for listing an IP address differ from DNSBL to DNSBL, as such, the requirements for de-listing are specific to the list you have been added to. You can check your IP address on the DNSBL website.

Most blacklist database will give you general listing reasons but not the specific email addresses connected to the blacklisted IP addresses. On the other hand, when you do not know what the issue is and before you make contact to de-list, try to ensure the following are done first:

  • Scan computers and devices you connect to the internet for malware and virus
  • Reach out to those using your connection by inquiring: whether there are large number of emails sent out that may be considered spam? Or whether someone is repeating a manual task that sent out too many connections from your IP to the host server?
  • Investigate software updates that needs to be installed manually
  • Organize routers more securely

How to Prevent an IP Address Blacklisted from Happening

There are various methods that reduce the chances of an IP address blacklisted. These include: security conscious procedures, encrypted communication and user authentication. Let’s look at some other reasons:

1. Have a strong password

Always practice using stronger passwords that contains uppercase and lowercase letters, numbers and symbols. Spammers sometimes perform dictionary attacks on mail servers to guess a password and take over the account.

2. Use a trusted Host and trusted IPs

Security settings excuses trusted hosts and trusted IPs so be careful not to place a host or IP you do not trust as this could possibly open the door for your server to become vulnerable and start sending out spam.

3. Use a firewall

Configure your firewall to log outbound activity from all machines on your network to track machines that are relaying mails.

4. Use IP shield

Configure your IP shield to only accept mails from your local domain once it came from an authorised IP address. Your IP Shield allows you to stipulate IP addresses or IP ranges allowed to send email for a specific domain.

5. Prevent Relaying

Ensure that your server does not relay mails. Spammers exploit open relays. Relaying happens when a mail that is not going to your local server nor was sent to a local account is sent through your mail servers.

6. Get an SSL certificate

SSL certificates encrypt the connection between a mailing client and the server. This is very useful if protecting your IP address. To learn more about why every website needs an SSL certificate, read here.


Now that you have more knowledge of what IP address blacklisting is you can better prevent it and reduces your chances of falling into this undesirable situation. Just ensure you have all the preventative measures in place to secure you IP address.