How To Block Robots From Indexing Sub-domain With Robots.txt?

Hi,

I have a website that is framing content from a subdomain i.e.

example.com is framing content from sub.example.com.

What is the correct way to block robots from indexing these sub-domains?

For example, blocking files in the directories with robots.txt is easy

User-agent: *
Disallow: /administrator/
Disallow: /cache/
Disallow: /components/
Disallow: /images/
Disallow: /includes/
Disallow: /installation/
Disallow: /language/
Disallow: /libraries/
Disallow: /media/
Disallow: /modules/
Disallow: /plugins/
Disallow: /templates/
Disallow: /tmp/
Disallow: /xmlrpc/

but how do you disallow a sub domain and various directories and files in this sub domain with robots.txt?

For your info, I am using Joomla and Drupal CMS.

Thanks for your help.

Happy New Year 2009 to all members!