When you have several domains with different extensions and you need all of them to open exactly the same website, you can have the site under one of them and forward the others. There are a number of ways to forward one Internet domain name to another, like the so-called domain parking. When your web hosting package deal permits it, though, it will be better if you host each of the domains and create a URL redirect, not a domain redirect. The real difference between the two is that while a domain name is hosted, you may still have content for it, set up subdomains, email addresses, etc., while with a parked domain you can't do any of these things. For instance, if you're building localized sites under various country-code Internet domain names, you'll be able to work on them, but in the meantime, people will be redirected to the primary site.