Hi, I'm on a shared hosting. I was wondering, if I purchase a personal nameserver(DNS, ns1/ns2.myhostingdomain), am I able to provide the email/url forwarding services for my client if their domain's DNS is set to my nameserver?

Also, am I able to write a script(in PHP) to change where they want to forward their URL, email aliases... ???

Thanks for answring. :)

It sounds like you do have the technology to do that.

I think the web host won't allow unless you paid for another new account to host the domain

why don't you look at one of the domain services like Ultradns.com. You can purchase blocks of domain space, have a GUI that even your customers can use and give your customers permission over their own domains.