When you have several domains with different extensions and you need all of them to open the same website, you can have the website under one of them and redirect the rest. There are several methods to forward one Internet domain name to another, including the so-called domain parking. If your web hosting package deal permits it, though, it'll be better if you host all of the domains and set up a URL redirect, not a domain redirect. The main difference between the two is that while a domain name is hosted, you could still have content for it, set up subdomains, email addresses, etc., while with a parked domain it's not possible to do any of these things. For example, if you are 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 forwarded to the main site.