6 Reasons Why a Domain or IP address gets blacklisted?

Published on 2020-06-03Β· Updated on 2023-09-06

Introduction

It is always worrisome for business if domain name or server IP address gets blacklisted and sometimes the reason behind those blacklisting remains unknown to us.

So what can be the root cause that this Domain name/IP gets blacklisted?

In this tutorial, you will be learning about what is a blacklist? How this blacklist work behind the scenes? How can you check whether your domain is listed or not? And what can be done to remove them from blacklisting?

Before you can move forward, I would recommend you to learn a bit about spam which can be directly or indirectly related to domain name getting blacklisted.

How is Email Spam directly related to domain blacklisting?

Email Spams are unwanted, irrelevant messages that are bombarded or sent in bulk to users, including subscribers and unsubscribers. Since these messages are unimportant and users have never subscribed earlier, they might report this as spam. The increase in spam complaints helps ISPs to directly move your IP address or domain name in the blacklist; this results in degradation of the domain reputation and server IP.

The blacklisting can be due to any reason, some of them include, the issue with email headers, content, the from address, server from where the Email was generated initially, and many such similar pointers.

In most of the scenarios, it acts as a sign of improper server settings or issues with the email server which you might have owned or rented, or maybe you might not have followed Email sending guidelines. You can learn more about email spam from the previous tutorials.

Email Spam continues to be an ever-evolving issue, which can be understandable and solved while following guidelines that can help you save your domain name and IP address getting blacklisted on Global Realtime Blackhole Lists (DNSBLs).

What is Blacklisting and how your IP gets listed?

From the user's perspective, let's assume you are receiving lots of spam so what will be your first step to stop that?

There can be two ways one you block the sender another report that Email as spam and if you perform these step for few more time the ISP (internet service providers (Gmail, yahoo, outlook)) will automatically add that domain name or IP in the spam list.

But when it comes to prevention mechanism, the first step that an email administrative does is simply block that 'IP' address or Domain name which looks suspicious. To make this process clean and secure the idea of centralizing and crowdsourcing, the data was fostered, which resulted in the birth of DNSBLs.

DNSBLs can be said as web cops who monitor IP address and Domain name, and if they follow something that is against RBL rules, they have the right to put those IP or domain in their list.

Almost every DNSBLs maintain their own set of rules on which they operate, mostly DNSBL has categories related to abuse or spam. These DNSBLs have a variety of methods to collect the suspicious IP address, which doesn't follow the rules or engage with hacking, botnets, or malware.

If your IP is spotted or listed in the DNSBL list then earlier, your IP might be used for sending spam or used for email traps, honeypot, or botnet analysis.

Working with IP Address Lookups?

As mentioned earlier, every DNSBL follow their own set of rules and basis on that rules they add IP in their list. The Domain reputation is open to the public so that they look up their IP/domain name and check the reason for getting listed.

DNS servers originally meant for domain lookups only, but due to high scalability and low overhead, it gains a considerable reputation for looking up IP as well.

Checking the lookups technically:

1. Reverse an IP address
2. add the DNSBL domain after the IP address.
3. Do Lookup for resulting domain

if your domain is listed then an IP address will be returned, but if it is not listed then, the result will be "NXDOMAIN/Non-existent domain."

IP address (1.12.103.153):

Name:     153.103.12.1.zen.spamhaus.org
Address:  127.0.0.10

A domain which is not listed is as follows:

IP address (8.8.8.8):

Name:      8.8.8.8.zen.spamhaus.org
*** server can’t find 8.8.8.8.zen.spamhaus.org: Non-existent domain

What is the actual command used to get the result?

dig a +short (domain.name).(blacklist-domain-name) @(ns IP)[optional]

ie. dig a +short example.com.hostkarma.junkemailfilter.com
//resulting output
127.0.0.1
127.0.0.3
127.0.0.2
127.0.0.5
127.0.1.1
127.0.1.2
127.0.1.3
127.0.1.4
127.0.2.1
127.0.2.2
127.0.2.3

Different DNSBLs have different ways of handling the responses. To confirm whether the domain is registered or not, it is recommended to look upon other sources as well which includes list of DNSBLs.

Luckily, you don't have to check this technical accept as of now because Pepipost has already done it for you. You can simply visit tools.pepipost.com and hit enter by adding your domain in the search bar you will find all the DNSBL which includes both listed and unlisted.
Not only that you can also find why your domain is listed and how you can delist them!

Also, you can always download the list of domains N number of times that to free!

6 Reasons why a domain or IP gets blacklisted?

After many years of digital transformation, Email remains one of the most prime channels for interactions, generating leads and authenticated way of excelling the brand.

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Vikram Sahu πŸ¦‰

Developer Evangelist, Pepipost

πŸ’» Senior Software engineer β†’ πŸ₯‘ Developer Relations guy β†’ πŸ€“ Building Community for Email Geeks 🎟 β†’ Speaker πŸŽ™

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