As many know, DNS corresponds to domain name system. It is a method for converting domain names to IP addresses, which are numbers that identify elements in the network, such as servers, computers, etc. All computers and devices are connected to the Internet IP address, and what makes DNS is to prevent people from having to remember all those numbers, and instead change it to names that you can remember easily. Put another way, it is easier to remember google.com to the IP address 126.96.36.199. With so many domain names as big as Internet, remember all the IP addresses would be virtually impossible, plus some cash.
The call spoofing is a cheating method that is used to make a target to be confused with something else. On the Internet, this practice is done to make it appear that mails are sent by someone who is not actually being sent. When we talk about DNS spoofing is the practice of making an address resolves to a different IP address than it actually is. This can be done for legitimate reasons or you can do for darker motives. For example, some network equipment let you spoofing DNS to allow a server to act as a proxy DNS as an interface to an ISP is not operational. When the interface is working again, requests are again sent to the DNS network.
However, there are people using this system to fool people who surf the Internet. Often, one wants to deceive Internet users into believing that you have reached the website I thought, which is not true. Usually this method is used to obtain passwords, account numbers and other information that can then be exploited by spoofing. Needless to say you have to be careful with this.
There is some confusion between different ways to use this technique. There are systems that take the user to a different web site, though not necessarily want to cheat. For example, it is used by many companies when you cannot find a URL. Often it is because there has been a problem and the URL is no longer valid. In this case, the user replace the page that has nothing to do with the topic. Put another way, the Internet user is forwarded to a page if it exists and is valid.