accessing website hosted by externally

Hi,

How do I configure dns so that internal clients can access our website that’s host by our isp? Our domain name for our internal network is (domain.com) the same as our domain name for our website (www.domain.com) which causes the conflict. I know I can add a record to the client’s local host file and have it point to the webserver but it’s too time consuming. I was hoping there’s an easier way through dns. I’ve tried creating a CNAME but that didn’t work, maybe I’m doing it wrong.

Wealso have a simple intranet on our internal network. So when clients try to access our website (www.domain.com)it goes straight to the internal website. How to bypass this?

I’m new to DNS so please be as detail as possible.