Redirection for non-existent subdomains

I tried to log in to a customer account with http://cp.mycustomersaccount.com and got a completely different website. Okay, maybe it’s not the right way to log in, but…

To see what happens, try http://nodomain.jodoshared.com

Do I need to set up a cp domain alias on every user account (if so, to where?), or do i let them use cp.myreselleraccount.net:8080 to log in?

I’m on win5.

I use cp.myreselleraccount.com:8080.

I think that it is the right way do go.