Doing a website redirect using DNS

Does anyone know a way to redirect a website without actually changing the HTML page and using the REDIRECT tag?

For example, is it possible to do a redirect from http://siteA.olddomain.com to http://siteA.newdomain.com by re-configuring DNS records?

Many thanks

Yes, thats what CNAME records are for. If you have a virtual site many providers also offern Domain Forwarding with URL masking but this isn't a true solution and probably not what you are looking for. There are some good providers for doing this and I've used one now since 1996 - Autoforward.com. I have stayed with this guy mostly cause I've been there since he started the company and I've got to know him. In any case he allows you complete control over your dns so you can add cname records, mx records, forwarders, etc.