DNS-Hijacking

A DNS hijacking ( for target systems. Hijack to kidnap ) denotes an interference with the function of the Domain Name System, are added at the intentionally incorrect answers.

Positive response despite negative data

A case of several Internet service providers (telecom, Alice, Versatel ) common practice is to ( NXDOMAIN ) does not return DNS requests for domain names that are definitely not reported existent by the parent, authoritative name servers than with this same error message to the client, but instead to supply the address of an own homepage. If the original request was made ​​to retrieve a Web page in preparation with a browser, this means that the user gets, for example, displays a search page of the provider instead of an error message. A developer of this method calls it "Web Error Redirection ". The problem with this technique, however, that non- Web -based Internet services with no intention of domain ownership in this form data to be supplied and this just may cause the failure of an error message unexpected behavior. How could a mobile Windows computer with positive answers to certain DNS requests incorrectly assume to be located in the (safe) local network. In the current service providers, it is possible to disable the said feature.

On the client side there is this function also in some browser extensions.

Malicious redirection

In addition to this imaginary as a customer service forwarding on non-existent domains is redirected by some malicious softwares also in actually existent domains. For example, this is done to prevent the downloading of antivirus software, to display advertising or to redirect the user to a replica of the actual desired web page and so gain access to confidential data (phishing).