When you have a lot of domains with different extensions and you need all of them to open the exact same Internet site, you can have the site under one of them and redirect the rest. There are a number of methods to forward one domain name to another, among them the so-called domain parking. If your hosting package allows it, though, it'll be better if you host all of the domains and create a URL redirect, not a domain redirect. The real difference between the two is that while a domain address is hosted, you can still have content for it, set up subdomains, email addresses, and so on., while with a parked domain it's not possible to do any of those things. As an example, if you are building localized Internet sites under several country-code domains, you shall be able to work on them, but meanwhile, people shall be redirected to the main website.