Craft pieces accessed by people on domain only How would you make portions of Craft available to only people that are "on the domain" and then let the rest of it be public facing? Would you need two instances of craft on 2 servers? One which is accessible only from "inside" and another that the public can access?

Would this entail running Craft on one webserver and the front-end on another? This way the webserver with craft on it is only accessed internally but the front-end can be accessed outside?

edit: I only want CP to be accessed by people who are logged in and on the work network. For security reasons a simple login is not enough.
The back end of craft (admin log in section or Control Panel) can only be accessed by admins and users that an admin has added. The front end will always be visible to everyone while the backend will be password protected. 

If you want separate front end displays for people who have usernames and passwords and those who dont, you could add a front end log in form:

http://buildwithcraft.com/docs/templating/login-form

And display one set of templates for those who are logged in and another for those who arent logged in via conditional statements e.g. 

{% if currentUser %} 
  Protected info 
{% else %} 
  public Info 
{% endif %} 

If this isn't quite the answer you're looking for could you be slightly more specific with what you mean by "on the domain". Describe exactly what you're looking to achieve.