DNS redirection was the controversial practice of serving a Web page to a user that is different from either the one requested or one that might reasonably be expected. In the early days of the internet, an ISP would typically serve an ad-based page when the user mistyped a URL, rather than a 404 error message,
In July 2009, Comcast announced it would test DNS redirection, under the name "Domain Name Helper Service," in Arizona, Colorado, New Mexico, Oregon, Texas, Utah, and Washington. Other ISPs that implemented DNS redirection include Verizon, Cox, Earthlink and Charter. The practice was generally not popular among consumers and is no longer a source of revenue for ISPs.
DNS redirection differs from DNS poisoning, in which an attacker gains access to a server's DNS table and substitutes a rogue address for a valid one. Fake companies have been set up to sell billions of hijacked IP addresses. Fraud, forgery and identity theft are involved with these hijackings.
The recent rise in DNS poisoning, also referred to as IP hijacking, can partially be attributed to hackers who find the WHOIS database an easy target. By making unauthorized changes to registration records, hackers have been able to hijack existing IP address ranges created before the American Registry for Internet Numbers' (ARIN's) inception in 1997. At that point, a worm, spyware, Web browser hijacking program, or other malware can be downloaded to the user's computer from the rogue location.