Spamhaus is one of the most feared blacklists that will have any email sender quaking in their boots. Not only is it dreaded because of its ability to stop you from reaching your intended inboxes, but it’s because even the smartest and most sophisticated senders can still find themselves blacklisted here.
The main focus of Spamhaus is to monitor spam-like activity and spammers themselves. It is composed of several blacklists that are used by email providers to stay protected from potentially harmful emails. A key Spamhaus blocklist is called the ZEN list.
What Is the Spamhaus ZEN List?
The ZEN blacklist of Spamhaus is a combination of all IP blocklists from the entity. It is designed to provide a complete and powerful block list that makes the IP address lookup simpler and quicker.
The blacklist also contains the following blocklists:
- SBL
- SBLCSS
- XBL
- PBL
Understanding the ZEN Blacklist
As mentioned above, the ZEN blacklist is composed of the SBL, SBLCSS, XBL, and PBL blocklists.
The database called the Spamhaus Block List (SBL) is a repository of IP addresses that Spamhaus recommends email providers should avoid. This is because the spam monitoring entity may have deemed these IPs to be involved in sending an email that has spam-like tendencies.
Meanwhile, the Spamhaus SBLCSS provides a list of IP addresses that are marked to have sent low-reputation emails. Specifically, it lists those that have:
- Sent emails with indications of abuse or an unsolicited nature
- Sent bad emails caused by a compromise
- Poor email list hygiene
Additionally, the SBLCSS blocklist lists IP addresses based on multiple heuristics and events.
The Exploits Block List (XBL) from Spamhaus is a real-time database consisting of IP addresses from hijacked computers. The devices of these addresses are those that have been infected by illegal third-party exploits such as worms with built-in spam engines, open proxies, and Trojan horse varieties.
Then, there’s also the Spamhaus Policy Block List (PBL) which is a DNSBL usage database containing end-user IP address ranges. These addresses are flagged to not deliver unauthenticated emails to mail servers with the exception of those supplied specifically by an internet service provider for customer use.
Both static and dynamic IP address ranges are listed in the PBL so long as they qualify for free use. These are IPs that aren’t allowed to send emails directly to a third-party mail server.
How To Know If You Are Listed in Spamhaus
To find out if you have been listed in Spamhaus, you should visit the URL https://www.spamhaus.org/lookup/. Performing a lookup here should provide you with details of if you have been listed in any of the Spamhaus IP blocklists.
In the link, you can choose to enter either your IP address or your domain name. For the IP address, the lookup tool will check if you have been listed in the SBL, XBL, and/or PBL. Meanwhile, the domain lookup tool will check if your domain has been added to the Spamhaus Domain Blocklist (DBL).
Ways To Avoid Being Listed
It can be difficult to launch an investigation on what could have been the reason why you have been blacklisted in the Spamhaus ZEN listing. You can try talking to your technical support department or domain manager to have your IP address removed.
But, before asking to have your IP address removed from being blacklisted, you should first try to work out and fix the issue that caused you to be added in the first place.
Here are some things you can start to work on:
- Verify your sender infrastructure: You want to make sure that the authentication records of your domain, such as its SPF, DKIM, and DMARC, have been set up correctly and are working. You can use DMARC enforcement to stop receiving emails that contain phishing, malware, or other potentially harmful content that spammers can use to get your account blocked.
- Check and review your email list: Another thing you want to ensure is that you are sending emails to users who have chosen to opt-in to your email list. For even more security, consider using a double opt-in process.
- Practice good email hygiene: You should verify your email list and get rid of emails that have resulted in hard bounces as soon as possible. You can set up a system that automatically processes bounce emails.
- Manage your email list appropriately: Ensure that your unsubscribe process is working properly. You want people to be able to take themselves out of your mailing list whenever they want. If you have a way of checking recipient activity, you should pinpoint and get rid of users who are no longer interacting with your emails. But, before you go ahead and take out unengaged subscribers, you might want to send a re-engagement campaign first to try and win them back.
- Monitor proactively: Finally, you should keep track of complaint rates, spam trap hits, and bounce rates from all of the emails that you send. If you start to see high numbers of these reports popping up, it is best to resolve them right away before you get added to the Spamhaus ZEN blacklist.
What To Do If You’ve Been Blacklisted by Spamhaus
If you find yourself somehow blacklisted by Spamhaus, there are some things you can do to help yourself get delisted.
Take Action Immediately
As soon as you learn that you’ve been listed on the Spamhaus blacklist, you should start to take action immediately. This is because being included in any of their block lists can severely affect the deliverability of your emails.
The first thing you should do is to stop sending messages right away. You should then review the most recent email campaigns you’ve been using and see if there are any immediate issues you can pick up.
Communicate What Happened
It’s vital that you inform all parties that are part of your email program to know that your account has been added to the Spamhaus blocklist. Two of the most important entities to communicate with are your technical account manager and your email service provider.
Your technical account manager is particularly crucial to inform since they are usually experienced in dealing with Spamhaus. They can either provide you with tips on how you can get delisted or guide you down the right path.
Keep in mind that getting delisted means that you should fix the problem that has resulted in you being added to the blacklist. This is why it’s crucial that you learn and understand what could have gone wrong with your email campaign.
Apply for Delisting and Follow Through
There is a delist checklist that you should know to increase your chances of having your IP address removed from a blacklist. The checklist includes the following actions to take:
- First, confirm that your IP and domain is listed on Spamhaus
- Pinpoint which of your IPs and domains have been affected and stop sending emails with them
- Get assistance from your technical account manager and email provider
- Review all of the emails that you sent recently and look for clues on what may have caused you to trigger the blacklist
- Address the problem that has caused you to be blacklisted
After performing all of these actions, it’s time for you to get delisted from Spamhaus. Head to the Spamhaus lookup URL and then follow the instructions provided to get started.
While filling out the delisting form, you want to be brief and state that you’ve already addressed the problems that could have resulted in your IP address triggering their blacklist.
It’s important to keep in mind that Spamhaus has full authority on whether they will remove you from their list or not. Also, getting delisted doesn’t always mean that they’ll also take you off of their blacklist.
Once you’ve been removed from Spamhaus, you should work hard not to get into any of their lists again. You don’t want to get blacklisted again, especially since the consequences can be more severe the next time around.
That’s why proactive account monitoring is essential as an email sender. You want to ensure that your email campaign is healthy by practicing good email list hygiene. This alone can be significantly beneficial to help you avoid being flagged as potential spam.
Conclusion
Spamhaus uses many types of blacklists that can help it keep an eye on email senders that could be sending unsolicited emails. The ZEN blacklist is one of the most feared lists for any email sender today. Being added to this blacklist can have severe consequences for your ability to send emails.
That’s why it’s essential for you to follow the best practices for managing your email list to avoid getting marked by their block lists.
Want to know more about how you can prevent being flagged by Spamhaus? Read our post here for more details.
