In case you have a lot of domains with different extensions and you need all of them to open the very same site, you can have the site under one of them and redirect the rest. There are several ways to forward one domain to another, like the so-called domain parking. If your web hosting package permits it, though, it will be better if you host all the domains and set up a URL redirect, not a domain redirect. The primary difference between the two is that while a domain name is hosted, you may still have content for it, create subdomains, email addresses, and so forth., while with a parked domain you cannot do any of those things. For instance, if you're building localized websites under several country-code domains, you will be able to work on them, but in the meantime, visitors will be forwarded to the main Internet site.