URL redirection, also called URL forwarding, is a World Wide Web technique for making a web page available under more than one URL address. When a web browser attempts to open a URL that has been redirected, a page with a different URL is opened. Similarly, domain redirection or domain forwarding is when all pages in a URL domain are redirected to a different domain, as when wikipedia.com and wikipedia.net are automatically redirected to wikipedia.org.
URL redirection is done for various reasons:
for URL shortening; to prevent broken links when web pages are moved; to allow multiple domain names belonging to the same owner to refer to a single web site; to guide navigation into and out of a website; for privacy protection; and for hostile purposes such as phishing attacks or malware distribution.