When you have a few domains with different extensions and you would like all of them to open the same website, you could have the website under one of them and forward the others. There are various methods to redirect one domain name to another, such as the so-called domain parking. If your hosting package permits it, though, it shall be better if you host all the domains and set up a URL redirect, not a domain redirect. The difference between the two is that while a domain is hosted, you can still have content for it, create subdomains, e-mail addresses, and so forth., while with a parked domain it's not possible to do any of these things. For instance, if you're building localized Internet sites under various country-code Internet domain names, you will be able to work on them, but meanwhile, visitors shall be redirected to the primary Internet site.