Comprehensive and Detailed Spamhaus Blacklist Guide for Wise Marketers

Vladislav Podolyako
Jul 01, 2022
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Every email marketing campaign takes up a fair share of time, effort, and means that are put into it. So it generates successful conversion and proper user engagement. However, should your IP address get on a dedicated block list, the email deliverability scores will drop significantly 📉. While your target audience does not receive the marketing emails or sees them as potentially harmful spam, you can’t count on satisfactory ROI and general company revenue. The best way to escape the unfavorable outcome would be to learn all you can about the significant blacklists, and today we will discuss the Spamhaus blacklist and how to stay clear of it, in particular.

General description of a block list

Before proceeding with the Spamhaus blacklist, it needs to be explained what an email blacklist stands for. An email block list is a continuously updated database of domains along with the IP addresses that predetermines who is sending spam and then blocks the untrustworthy senders. Essentially, you can view a blacklist as a type of filter which decides where your messages should end when it comes to the consumer’s inbox. The more emails get into the Spam folder - the lower your reputation will get. And it will directly impact the drop in sales.

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Why does a spam message get blacklisted?

📮 While the general definition of a spam email indicates a potentially harmful message, there are slightly different connotations to the notion that you should be aware of. Some spam messages contain malicious links that can compromise the safety of your system. Very often, such emails ask the reader to carry out an action that will harm your system.

However, some spam is nothing more than various advertisements and marketing offers that you haven’t signed up for or have no interest in. While these messages bear no potential system threat, they clutter the inbox, which is something that most users want to get rid of. That is why most ISPs endorse spam filters and blacklists to keep unsolicited bulk email campaigns at bay and prevent them from getting into their network.

What is Spamhaus?

Spamhaus is an international IP and domain reputation checker that has been leading the market for almost 25 years now. The primary goal of the Spamhaus blocklist is to detect spam-like activity and eliminate potential threats. More than one block lists run under the Spamhaus name, and leading mailbox providers access them via DNS.

How does the Spamhaus blacklist work?

Spamhaus blacklist algorithm is designed to check IP addresses in real-time and detect potentially dangerous sources. The sole purpose of the Spamhaus blocklist is to ensure that Spamhaus users reduce traffic from those IP addresses that feature a reputation of spam vendors.

Spamhaus project is known to cooperate well with the Internet community. Aside from that, the Spamhaus blacklist service features an impressive sensor network designed to gather connection details across different networks, which cover popular ISPs and various government enterprises. Besides, every Spamhaus blocklist monitors internal spam traps for the same reason.

To detect whether specific IP addresses are guilty of sending spam, Spamhaus applies a plethora of techniques to the process. The techniques range from manual data investigation to machine learning. 💻

Why do you end up on Spamhaus IP blocklists?

Now, when you know what a Spamhaus blacklist is, you may wonder what kind of IP address is the most prone to end up on the block list and why your IP address arises suspicion. There are a few major reasons to be aware of:

Reason 1: Compromised addresses or lists

The moment when an ISP notices a few cases of bounced addresses, it decides that there is something wrong with the email list. Spamhaus, in its turn, works on any address space and is programmed to detect spammers with special secret email addresses used as "spam traps". A spam trap address is an address that no one uses. However, such addresses are publicly available, so some people use them to build and sell mailing lists. If you start sending mail to such a compiled and usually outdated list, the Spamhaus blocklist will flag you as a spammer who hasn’t got users’ consent to send out marketing propositions. This is when your IP address gets on the Spamhaus block list.

Here’s what the process looks like in real life:

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Step 1: A spam trap address is added to the mailing list

Spammers often use extended mailing lists that contain countless reputable addresses taken from official websites. Besides, it is common for spammers to buy address lists on the underground market. Spamhaus blacklist has a peculiar set of emails 📝 known as spam traps, considering all the potential risks of spam emails. Those spam traps are well-advertised so that spammers grab them and introduce them to their own mailing lists.

Step 2: Spam initiation

Once a spammer starts sending spam with the spam trap added to the list, the Spamhaus blacklist activates.

Step 3: the IP address gets listed

Before the spam message is successfully delivered, the spamming malware is supposed to tell the spam trap mail server where the email should be delivered to. As the spam trap server gets the trap address, the IP is automatically added to the block list.

Reason 2: Spam complaints

Even if you are not sending spam, you may still end up being blacklisted. All die to users’ complaints. Once a recipient flags your incoming email as spam, the Spamhaus system will get a type of notification. Your IP address will inevitably be added to the blacklist if such complaints pile up.

Reason 3: Rapid increase in list size

If you want to keep away from the Spamhaus blocklist along with other blacklists, you may want to monitor the size of your mailing list. It is unadvised to go from a couple of outcoming emails daily to hundreds of messages per day within an overly short period. The primary suggestion that will occur to an ISP would be that the mailing list is pre-bought, thus, potentially spam-like and dangerous.

Reason 4: Using the same address by different people

The problem could also be that multiple users end up sharing a single public IP address through a process called NAT. If you're currently sharing—or recently shared—an IP address with a user whose machine sent spam, then it's possible that the IP address has been blocklisted.

Steps to take when your IP address ends up on the Spamhaus blacklist?

Even if you are not sending spam out, you may suspect that there is something wrong with your IP address, since the marketing stats you get are significantly lower than expected. The primary thing that the experts advise doing is inspecting your IP address for potential reputation drops 🧐. Once you confirm that your IP has been blacklisted, you can reach out to Spamhaus and inquire that your IP is to be removed from the list.

Those of you who do not own an email server should get in touch with the ISP that the IP addresses in use are assigned to and ask for help. In case you have your own server at your disposal, you can inquire that the domain reputation checker inspects your IPs and provides available data on why the IP is blocked.

Take these steps to figure out if any of your IP addresses are on the IP and domain block list owned by Spamhaus:

Start a blocklist checkup

To solve the problem of being blacklisted, users usually start with accessing the Blocklist Removal Center. Add one of the IP addresses you are worried about to the search box, and before the system exploits the block list, press the Lookup button. If your IP is presented on the blacklist, a warning message from Spamhaus will come up indicating the issue.

To decide whether you are in desperate need of a new IP address, you need to determine how difficult the situation is. Once you click on the Show Details menu, the system will provide an in-depth review of why the IP is listed and what you can do to improve the situation. However, if you are not the owner of the mail server, you will have to get in touch with the ISP to resolve the matter. 

Determine the block reason

There are other reasons than spam operations that can force the Spamhaus blacklist to doubt your reputation. There are cases when the blocklist investigates IP addresses for security reasons. If you find your IP on an XBL or SBL list, that would be the security case. Thus, you will have to browse through the server logs to detect any suspicious activity within and outside the network. 🔐

Once you find the underlying cause of being blacklisted, you have to fix it and ask the Spamhaus blacklist to remove your IP from its database.  

Removal request

To request removal is quite basic at its core. All it takes is to access the Spamhaus blacklist, fill out the removal form, indicate your contact information, and click the Submit button. Once the form is accepted, the removal process will be initiated straight away. Usually, it takes for the system to finish the process within 24 hours. In case you find your IPs on the block list after 24 hours, you may want to get in touch with a Spamhaus representative and ask for assistance.

How to keep your IP addresses off the Spamhaus blacklist?

💡 No matter how simple the process of getting out of the blacklist seems, there may be some complications along the way. One way to ensure that everything goes smoothly, and your reputation is restored, would be to assign the technical support team with the removal task. However, there is something else, especially if there is no technical team to refer to. You may want to do your best to keep your IP addresses out of such dangerous situations. Consider the following tips, which have proved to be more than effective:

Confirm sender infrastructure

Very often, senders leave the notion of authentication records out. However, with such essential records as DKIM, SPF, and DMARC intact, you will ensure the domain’s safety. Besides, DMARC records will help you eliminate even the minor threat that comes from third-party phishing and spamming attacks, which can have your account blocked. Thus, before the blacklist situation arises, you should add the authentication records to the scene and check if they are working correctly from time to time.

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Inspect the email list

It is possible that you may end up on the Spamhaus blacklist if your users haven’t confirmed the opt-in feature that concerns your mail list. Sending marketing emails to those people who aren’t potentially interested in the offer may lead to a spike in Spam reports, and that would get most of the existing IP addressed to a block list in no time. So, the experts suggest you use double opt-in to decrease the chances of such an unfavorable outcome.

Proper email hygiene

One of the surest ways to end up listed on the Spamhaus blacklist is to invest in email lists sold online. Lists like that are filled with inactive or incorrect addresses, for the most part. Thus, sending your marketing emails to such addresses will lead to an increase in hard bounces, and that is a straight way to raise suspicion. 📥

Email list management

Even if your list is manually compiled, it needs to be adequately managed to keep off the Spamhaus’s radar. The primary thing to ensure is that your users can unsubscribe from you at any moment. If the person is no longer curious about your offers, they should be able to stop the stream of incoming advertising messages from you. In another case, a client will simply press the Spam button to stop receiving emails from you, then you will be blacklisted.

Monitor the stats

There is a reason why marketing reports and analytics are all the rage at the moment. If you don’t track the open rates, spam complaints, and bounce rates, you will have a poor vision of how well the campaign is going. Yet, if you monitor all the reports closely, you will spot any potential issue before it leads to some major damage. The monitoring practice has proved to be really effective.

Changing your IP address

What can you do if you are unable to remove your IP address from the blacklist? Most people decide to change their IP. And this is really a great solution to the problem.

You can get a new IP address in different ways, it all depends on what kind of Internet user you are.

🔄 Here are the most common ways:

  • If you are a local ISP or mobile user, then try reusing your IP address by "renewing your DHCP lease"; if that doesn't help, ask your ISP for a new IP address.
  • As a user of a commercial ISP, contact your ISP and ask for a new static IP address.
  • As a cloud hosting user, you can send your email through a service like SendGrid.
  • A dedicated hosting user should check other IPs near yours. If there are others on the list, you may have been dragged along. Ask to be transferred to a new subnet, if possible.

Final words

There are a lot of reasons why your IP addresses end up blacklisted. And not all of them necessarily mean that you are spamming your users. These days, all the major ISPs support outbound spam filtering to assist their clients to determine if they are sending spam. Yet, should you find yourself on one of the Spamhaus blacklists, the removal process is user-oriented and pretty straightforward. However, the effects of being blacklisted should not be underestimated in any way, and you have to do your best to keep away from it.

Read Folderly Outbound to make sure that your marketing campaigns are as safe and productive as possible!

Vladislav Podolyako
Vladislav Podolyako
Founder & CEO
Vlad’s decades of entrepreneurial wisdom and business building experience have allowed him to successfully mentor a diverse group of business owners, entrepreneurs in growing their companies. A recognized expert in the areas of transforming organizational culture and leadership development, B2B Sales, Marketing, spent more than 10 years building technology products, with a background in communication networks and electronic device engineering.

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