To create a sub domain cpanel asks for the name you wish to use. MAKE SURE the subdomain name you give it doesn't have a folder already named that name. If it does the sub will not work. Example... I want to create the subdomain test.aussie.com so my sub name is going to be test. If I already have a folder in my ftp named test I need to delete it or rename it to something different before I create the subdomain with the test name from cpanel.
You cannot create an addon domain if your dns hasn't proprograted to the server already. So after you change the sites dns you are trying to add you will need to wait 24-48 hours before attempting to create your addon domain.
There are three fields cpanel asks for when creating an addon domain.
1. "New Domain Name:" You will put in the newdomain.com do not put www in the name!
2. "Username/directory/subdomain Name:" This will be the folder cpanel creates in your main accounts ftp. MAKE SURE that the name you give it doesn't already have a folder. Example... If you want to give it the username chris. You cannot have a folder in your account named chris already. If you do and still try creating the username for the addon domain to be chris you will mess a lot of things up!!!
3. "Password:" fill in any password you want here
www.domain.com is a domain name. A subdomain is anything that replaces the www in a domain name.forum.aol.com is a subdomain.
www.forum.aol.com is not a subdomain.
An addon domain is a fully functional domain that will work from a folder with in your main site.
It creates it as a subdomain by creating the folder within your main sites ftp. Please ignore this! It is a fully functional domain name. It is only called a subdomain when in fact it is an addon domain.
