ER - Email Pro allows you to permit specific Email domains to register to your site. By simply adding a list of specific email domains such as @hotmail.com, @gmail.com, @jvitals.com will only allow people with those 2 email extensions to register to your site. If they do not have the specified email extension, they will not be able to register.
This addon is great for the more private sites such as companies that only want their employees to register.
THIS ADDON REQUIRES EXTENDEDREG TO TO BE INSTALLED FIRST