When you have a number of domain names with different extensions and you need all of them to open exactly the same website, you could have the Internet site under one of them and forward all the rest. There are different methods to forward one domain to another, like the so-called domain parking. When 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 real difference between the two is that while a domain address is hosted, you can still have content for it, create subdomains, e-mail addresses, etc., while with a parked domain you can't do any of those things. For example, if you're building localized sites under different country-code domain names, you will be able to work on them, but meanwhile, people will be redirected to the primary website.