Spamhaus is a threat intelligence organization that specializes in tracking spam sources, malicious domains, and internet infrastructure associated with cyber threats. The organization operates a suite of DNS-based blocklists (DNSBLs) and datasets that are used by email providers, internet service providers, enterprises, and network operators to filter spam, block malicious traffic, and protect network infrastructure. Core products include the Spamhaus Blocklist (SBL), Exploits Blocklist (XBL), Domain Blocklist (DBL), Combined Spam Sources (CSS), Policy Blocklist (PBL), ZEN Blocklist, Botnet Controller List (BCL), and the Do Not Route or Peer (DROP) list. These are made available both as free datasets under a fair use policy and as commercial-grade offerings via a Data Query Service, DNS Response Policy Zones (DNS Firewall), and an Intelligence API. Spamhaus gathers data from a global network of contributors including independent threat hunters, hosting providers, email service providers, law enforcement agencies, enterprise businesses, and in-house spamtraps. Data analysis combines machine learning, heuristics, and manual investigation by an internal team of security researchers and threat hunters. The organization processes substantial data volumes daily, including tracking 280 million domains, analyzing 7.5 billion SMTP connections, processing 22,000 malware samples, and generating 650,000 new detections related to exploited IPs. Its reputation data covers both IP addresses and domains and is used for threat investigation, detection, and network protection. Spamhaus also operates a Threat Intel Community portal for external submission of suspicious activity.