When some sites are undergoing maintainance a user may see an "under maintainance come back later" message when visiting the site. Most of the time they'll see this message no matter what part of the site they try to visit. I'm still very dinosaur when it comes to web design so I still write everything by hand and when I do have some php I need to work on I need to work on it live. Sometimes however I want to be able to work on the site or make updates without having people be able to interact with the site... I want to do this without renaming any files (esp. the index file), any directories, or moving anything around. How is it done?