1. Yes. cname.theirsite.com resolves to myserver.com.mysite.com which in turn resolves to an IP address. Browsers will send requests to your server at that IP a

1. Yes. cname.theirsite.com resolves to myserver.com.mysite.com which in turn resolves to an IP address. Browsers will send requests to your server at that IP along with cname.theirsite.com in "Host" header. 2. I'm not totally sure. I would start with wikipedia: http://en.wikipedia.org/wiki/Domain_Name_System http://en.wikipedia.org/wiki/Domain_Name_System Users will likely ask for help, so you'll probably want to familiarize yourself with the UIs for major DNS providers, especially GoDaddy. Another gotcha is that CNAMEs can be a little funky for root domains. So something.com will be harder (or impossible) for people to CNAME than foo.something.com depending on their provider. I've been told that CNAMEing the root domain means that all records (like MX) get automatically aliased as well, but I haven't found that to be uniformly true. My guess is that it depends on the DNS software.