https://ipv4mall.com/technology/what-is-ipv4-blacklisting/
IPv4 address blacklisting is a very common practice in the IPv4 marketplace these days. Most of us would have experienced networking attacks in one form or the other, such as malware, phishing, spam emails, or ransomware attacks. These malicious attacks originate from a local computer using the internet (meaning an IP address) and find their way to yours. There are many dedicated organizations, which track down such IPv4 addresses that are used for spamming or networking attacks. They have public databases of the blacklisted IPv4 addresses, which can be used by anyone to block connections from suspicious IPs. Some ISPs and private companies also provide a list of blacklisted IPv4 addresses to help make their network safer for the users.[…]
