Changing your hosts file is a great way to test your site before you go live.
On Windows operating systems you can normally find your hosts file here: C:\Windows\System32\drivers\etc
Then by adding extra rows like this:
You can map your domain (www.xyz.co.uk) to your new IP address without changing your DNS settings.
Obviously this will only work with each PC or laptop – it doesn’t change the way the rest of the world sees your website – but then that’s what you want!
Take a bit of care here though. Both your operating system and your browser can get a bit confused here. They are both busy caching DNS entries so they can produce odd results. If you run into trouble trying flushing the dns cache of your operating system (windows ipconfig /flushdns) and your browser.
Great for testing your 301 redirects before launch.