DNS cache poisoning, or DNS spoofing, is a hacker technique that fools a DNS server into thinking that it has received a valid and authentic response to a request. The poisoned DNS server will cache the information. Users are then redirected to questionable websites, which can be used for phishing purposes or as a channel to install a virus. Generally, the attacker exploits a vulnerability in the DNS server that would accept imprecise or false requests. The victims, who are expecting to see the website they wanted, are instead shown other potentially dangerous content. Generally, a DNS server has a port 53. The maximum size of a response must be 512 bytes. If it exceeds this size, the query is returned on TCP port 53. However, this type of redirection is rare, as hosting providers restrict the ability to transfer DNS zones in this way. Enable DNSSEC