What is a Spamhaus Block List?
Spamhaus Block List is an authoritative source of information for finding spammers who indulge in phishing, spoofing, and spam attacks. The list has a collection of IPs spammers use to send spam emails. It finds spammers effectively, and its real-time threat protection protects over 3 billion email accounts.
Spamhaus tracks a wide range of spammers, including spam content hosting services, spam services, spam gangs, IPs caught by Spamhaus spam traps, etc.
For this reason, many email behemoths like Gmail and Apple Mail use SBL to find spammers’ IPs, and if yours ever gets listed in SBL, email clients will reject or mark your email as spam.
How does the Spamhaus Block List work?
Spamhaus checks for spam-like activity and stores the IPs that indulge in any of the following activities.
Spam hosting: IP’s that host websites on which spammers have advertised or placed unsecure content.
Spam operations: IPs involved in the spam operations listed in the Spamhaus Register of Known Spam Operations (ROKSO). A few examples include Amoroso Corporation, AtomPark Software, Inc., and BadCow / mAiLIEN.
Spam services: Do you sell paid email lists, email scrapers, email appenders, or similar services? If so, then Spamhaus will block your IP and domain since it considers these services to be spam promoting.
Security threats: IP addresses that pose security threats to Spamhaus users, including phishing sites, ransomware, hacking attempts, etc.
So when Spamhaus considers so many factors to identify spam IPs, are you doubtful whether you've accidentally violated any rules and landed in SBL?
Well, leave guesswork aside, and let's learn how to know for sure if your IP is in the SBL.
Related guide: Everything You Need To Know About Email Security
How to check if your IP address is listed in Spamhaus Block List
Follow these steps to know if your IP is in SBL.
- Go to https://check.spamhaus.org/ and enter your domain name or IP address.

- If you see a Your IP has no issues message with a cute robot, you've nothing to worry about.

- But if it says your IP is listed in the SBL, you’ll see a message like this.

Source: Rackaid
To resolve this issue ASAP, you need to find the underlying reason and resolve it. More often than not, the main reason is a security breach that puts users’ data at risk.
5 ways to avoid landing on Spamhaus Block List
Here are the best practices you can follow to not end up on the Spamhaus Block List.
1. Check for security compromises
Even the biggest companies like Facebook have faced data breaches in the past. So if you are a victim of a data breach that compromised your users’ data, you’ll be blocked by Spamhaus.
Similar to data breaches, unencrypted emails and spoofed and phishing emails also cause major security concerns for your users. Spoofing and phishing techniques rely on social engineering to trick users and gain access to sensitive data.
Want to know how to safeguard your users’ data from being compromised? Incorporate the following tips in your campaigns.
Conduct employee security training to train your employees not to be tricked by spammers and cause security breaches.
Install an SSL (or TLS) certificate for your website and email server.
Set up authentication protocols such as SPF, DKIM, and DMARC.
Related guide: Email Security Best Practices to Keep Your Business Safe Today
2. Don’t send excessive emails
An average email user receives more than 100 emails per day. So your users may not like you sending an additional two emails every day because that’ll clutter their inboxes even more. But if you’re currently doing it or plan to do it in the future, be ready to receive a lot of spam complaints on your IP, getting blocked by the ISPs and SBL.
Apart from that, you shouldn’t send email blasts with a new email because that’s what spammers do. So to communicate yourself as a legit sender, you’ve to do domain warmup by sending a few emails with your new IP and increasing the number gradually. You can use an email cadence to figure out the sending schedule and plan accordingly. Additionally, you can use Google Postmaster Tools to check your sending reputation and ensure that your emails are not being marked as spam.
3. Avoid paid email lists
Buying an email list is a cardinal sin for email marketers. It goes against email laws such as GDPR and CAN-SPAM act, and you may face legal consequences and have to pay a fine in the magnitude of millions. Imagine how you'll feel when someone sells your email and strangers start sending you irrelevant emails. Not very pleasant, right? You’ll mark them as a spam source resulting in a decline in their IP reputation.
So if you insist on buying an email list to "speed up" your campaign success, you'll receive lots of spam complaints from those users, and Spamhaus will notice and won't remove your IP / domain from their list.
Related guide: What Is an Email List and How Can You Build it From Scratch
4. Setup authentication systems
If you haven't already, set up DMARC, DKIM, and SPF records in your email system.
DKIM assures that your email wasn’t modified while transmission. DMARC helps to prevent spoofing and phishing attacks. Finally, the SPF helps you establish yourself as the truthful owner of the emails.
So as you can see, these records are trust factors that establish your credibility as a genuine sender, and the chances of your IP or domain ending up SBL becomes tiny.
Related guide: Understanding Email Authentication Protocols: SPF, DKIM, and DMARC