Yes shared domain is what you need to use. Then, each client should be able to add their sub domain using the domain manager (not sub domain manager). I use this for clients who have not yet bought a domain but would like to view/work on their site.
The trick is you need to remember to add the new 'sub' domain as a cname record on your main domain. I'm not sure why the module wasn't coded to automatically add it
The trick is you need to remember to add the new 'sub' domain as a cname record on your main domain. I'm not sure why the module wasn't coded to automatically add it