When a browser connects to a website, it contacts a DNS server that converts the domain name to a numerical IP address; DNS redirection or hijacking programs subvert this process and return faulty information. DNS redirection often leads to phishing or other kinds of attacks.
A DNS redirection scheme can send a person looking to access his bank account online to a website that looks similar but is actually run by a third party. After the user tries to log in, the person perpetrating the attack has access to the user's login information. Not all DNS redirects are malicious; for example, companies that provide free Internet access might use a DNS redirect to make users accept the terms of service.