If you have a lot of domain names with different extensions and you need all of them to open the very same site, you may have the website under one of them and forward the others. There are several methods to forward one domain to another, like the so-called domain parking. If your hosting package deal allows it, though, it'll be better if you host each of the domains and set up a URL redirect, not a domain redirect. The primary difference between the two is that while a domain address is hosted, you may still have content for it, set up subdomains, email addresses, and many others., while with a parked domain you can't do any of these things. For instance, if you're building localized websites under different country-code Internet domain names, you'll be able to work on them, but at the same time, people shall be forwarded to the main Internet site.