An IP blacklist, also known as a DNSBL (Domain Name System Blacklist), is a list of IP addresses or entire network ranges that are known to be associated with malicious activity, such as sending spam or malware. When an email or other communication is received from an IP address on a blacklist, it may be automatically blocked or flagged for further review.
IP blacklists are an important tool for protecting networks and users from spam, phishing, and other online threats. They are used by email providers, website hosting companies, and other organizations to help keep their systems and users safe. IP blacklists are also used by law enforcement agencies to track down and prosecute cybercriminals.