If you have several domain names with different extensions and you need all of them to open the exact same site, you could have the website under one of them and redirect the others. There are various methods to redirect one domain name to another, among them the so-called domain parking. If your web hosting plan permits it, though, it'll be better if you host all the domains and create a URL redirect, not a domain redirect. The primary difference between the two is that while a domain is hosted, you may still have content for it, create subdomains, e mail addresses, and so forth., while with a parked domain you are unable to do any of these things. As an example, if you are building localized sites under several country-code domains, you shall be able to work on them, but meanwhile, people will be forwarded to the main Internet site.