Redirect it means a variety of ways through a variety of network requests the re-directions to other locations. Such as: domain name redirection page redirection routing change is also the path of data packets through a redirect on our website is under construction, often encounter the situation need to redirect web pages: as site adjustments, such as Web directory structure changes, the page is moved to a new address, and then, or, change the page extensions, such as the need for applications. php into. Html or. shtml, in this case, if not redirect, the user Favorites or search engine database only allows access to the old address will get a client error 404 page, access flow to lose; Another example is multiple domain names registered in some sites, but also need to access the domain name redirection user to automatically jump to the main site, and so on.