In case you have several domains with different extensions and you want all of them to open precisely the same site, you can have the site under one of them and forward all the rest. There are different methods to forward one domain to another, including the so-called domain parking. If your hosting package deal permits it, though, it shall be better if you host all of the domains and create a URL redirect, not a domain redirect. The main difference between the two is that while a domain name is hosted, you may still have content for it, create subdomains, e mail addresses, and many others., while with a parked domain you are unable to do any of those things. For instance, if you're building localized Internet sites under several country-code domains, you will be able to work on them, but at the same time, visitors will be redirected to the main Internet site.