I will be hosting web content for many client domains on a single IP address (with a web hosting company, not inhouse machine). Initially, I must give client some information to configure their registrar to point the domain to my server. I want client domains insulated from a potential IP address change, so if I change hosts/IP address they don't have to reconfigure anything with their registrar. Is this reasonably possible without running my own nameserver? If so, what would be the smartest way to make it happen? Instruct clients to make CNAME record? Use some type of DNS management service that clients would use as a nameserver?