Remove WWW prefix from your website

Question

How does Stack Overflow (and other web sites) remove the \'www\' prefix when it\'s entered as part of a URL?

Is it a redirect, a rewrite or something else entirely?<

Answer 1

Firing up Fiddler, we can see that the server responses with a "301 Moved Permanently" status and refers it to http://stackoverflow.com . Since StackOverflow is hosted on Windows 2k8 IIS7 they set up this redirect straight away in IIS7.

FYI:

a list of HTTP statuses

If you are a .NET developer you might know "Respose.Redirect" , this creates a 302 Object Moved status. Search engines like 301 status codes in this case better, because they know they should not come back to www.stackoverflow.com in the future.