Have you been blocked?
All blocklists are researched and managed by The Spamhaus Project.
Simply click on the link below, which will take you to the Project’s IP and Domain Reputation Checker. From here you will be able to enter your IP or Domain and begin your request for removal.
Please note that the Project’s IP and Domain Reputation Checker is the only place where removals are handled.
IT and security teams consistently face multiple business challenges. Discover how our solutions can help overcome some of those issues.
From processing issues, to email-borne threats our blocklists easily integrate with your current email set-up to improve anti-spam & anti-virus email filtering.
Employ our threat intelligence to increase visibility across security events, reveal potential weaknesses in your network, and threats to your brand.
Stay on top of the latest threats and proactively combat botnet infections, and other forms of abuse, with our solutions.
From clicking on phishing emails to visiting malware dropper sites, our threat intelligence provides automatic protection for your users.
Our products provide additional layers of security for networks and email. They also present security teams with additional insight into malicious behavior.
Border Gateway Protocol (BGP)
Block the worst of the worst at your network edge, taking advantage of your existing BGP-capable routers. Configuration only takes minutes.
Data Query Service (DQS)
Benefit from industry-leading real time blocklists. These DNSBLs easily plug into your existing email infrastructure to block spam and other email threats.
A powerful research tool to investigate relationships between internet infrastructures. Quickly pivot to new areas of concern to rapidly investigate potential threats.
Immediately block connections to dangerous sites, including phishing and malware dropper websites. A ‘set and forget’ solution.
Spamhaus Intelligence API
Threat intelligence data in API format to enable users to easily integrate metadata relating to threats with their own applications, programs, and products.
A wide range of datasets, providing multiple layers of protection. They can be plugged directly into your existing hardware, making them an affordable choice.
Border Gateway Protocol (BGP) Feeds
Do Not Route Or Peer (DROP) and Botnet Controller List (BCL) datafeeds can peer with your existing BGP-capable router.
Domain (DBL), Zero Reputation (ZRD) and Hash blocklists (HBL) enable you to block content in emails, filtering out a higher rate of email-borne threats.
Data for Investigation
Passive DNS and extended datasets give you additional information on internet resources. They provide deeper insights into incidents and possible threats.
DNS Firewall Threat Feeds
A wide range of feeds to apply to your DNS recursive server. Choose the right level of protection for your organization.
Spam (SBL), Policy (PBL), Exploits (XBL) and Auth (AuthBL) blocklists allow you to filter email from IPs associated with spam, botnets, and other threats.
Find out more about us.
Learn more about Spamhaus; who we are, and what we do.
Find out who we work with and how you can become a Spamhaus Partner.
Discover a wide range of blog posts, case studies and reports.
Commonly asked questions about Spamhaus products and processes.
The Blocklist Tester
A tool to help you check if your servers are correctly configured to use Spamhaus DNSBLs.
In depth information about the technical details and implementation of our products.
Posted by Matt Stith on 11 Nov 2020
You're running your own email infrastructure, or at least considering it, but how should email filtering be handled? What is your first line of defense against the spam and malicious emails that will bombard your mail server?
The answer is simple – Domain Name System Blocklists (DNSBLs). However, if you’re not familiar with DNSBLs, it’s not going to seem simple, or at least, not initially. Don’t worry. We’re going to revisit some blocklist fundamentals to bring you up to speed.
Firstly, let’s try and eliminate any confusion around terminology. Are they called “blacklists,” “blackhole lists,” “domain name system blocklists,” or “real-time blocklists”?
The answer is….all of the above (and probably more). However, for this article’s purpose, we’ll be referring to them as “DNSBLs” and the simplified version of “blocklist.”
The name gives it away; it’s a list, or more accurately, a database containing IP addresses, domains, or hashes. These lists are compiled by specialist research teams, who have observed the listed internet resources to either be:
Presented in a DNS zone, blocklists can be utilized by anyone managing their own email infrastructure. Fundamentally there are three stages where you should be using DNSBLs:
It all starts with data. Vast quantities of data. In fact, Spamhaus was dealing with ‘big data’ before ‘big-data’ became the buzzword we know it as today.
The industry and beyond shares data with Spamhaus, from hosting companies to Internet Service Providers (ISPs) and internet governing bodies. Of course, in addition to this Spamhaus runs its own spam traps and honeypots.
Through manual investigations, machine learning, and heuristics, our researchers analyze this data to see if it meets pre-defined policies for listing.
Before curating a DNSBL, Spamhaus decides on the criteria the IP, domain, or email content must meet for it to be listed. These criteria are referred to as “policies.”
Needless to say, these policies aren’t plucked out of thin air. Instead, they are formed in consultation with the wider internet industry (both senders and receivers) to ensure they are fit for purpose and meet internet users’ needs.
To understand the breadth of data processed by our research team to produce reliable and effective blocklists, here are some daily numbers:
The IPs, domains, or hashes associated with an email can be queried against a DNSBL to see if they’re listed. As someone managing the email infrastructure, it’s down to you to decide how to handle that potentially malicious email. You can either:
A. Reject the email in real-time, with an appropriate delivery code, or
B. Accept the message and tag it for additional filtering.
Read Understanding the source code of a malicious email to understand why certain parts of an email’s source code have specific blocklists applied to them.
As previously mentioned, blocklists contain either IPs, domains, or hashes. Here’s a quick overview of the types of blocklists produced by Spamhaus:
Spamhaus Blocklist (SBL) – IP addresses observed to be involved in numerous activities including sending spam, snowshoe spamming, botnet command & controllers alongside hijacked IP space.
eXploits Blocklist (XBL) – Individual IPs (/32s) that are infected with malware, worms, and Trojans etc. This list prevents mail servers from accepting connections from compromised computing devices.
Policy Blocklist (PBL) – IP addresses that shouldn’t be sending email e.g. internet of things (IoT) devices. Spamhaus works together with the industry, enabling IP owners to list and manage their own ranges for your safety.
Auth Blocklist (AuthBL) – IP addresses know to host bots using brute force or stolen SMTP-AUTH credentials to send malicious emails.
Domain Blocklist (DBL) – Domains owned by spammers, being used for nefarious purposes. We also list domains that are legitimate but have been hacked by bad actors and are being used with malicious intent.
Zero Reputation Domains (ZRD) – Domains that have been registered in the past 24 hours – helping you filter email from cybercriminals who register, and immediately use multiple domains on a daily basis.
Hash Blocklists (HBL) – A content blocklist that uses cryptographic hashes to list email addresses, cryptowallet addresses, and malware files.
After this tour of some blocklist basics, why not try the data yourself. Sign up for a free trial here.
Spamhaus’ Data Query Service (DQS) is an affordable and effective solution to protect your email infrastructure and users.
Using your existing email protection solution, you will be able to block spam and other related threats including malware, ransomware, and phishing emails.
The service has never failed and utilizes the longest established DNSBLs in the industry.
11 November 2020
Here are 11 ways to help email administrators make running their own email infrastructure a success.
Running your own mail server isn't for everyone. However there are advantages to be gained from brining email in-house.
10 November 2020
Spamhaus Know How | Join the experts on this webinar where they will step you through the fundamentals of DNS Blocklists and email filtering.