How to prevent a program from accessing to the Internet?

Sat Oct 18 15:57:43 UTC 2014

On Sat, Oct 18, 2014 at 14:09:41 +0100,
  Paul Smith <phhs80 at gmail.com> wrote:
>Dear All,
>
>I would like to prevent a program from accessing to the Internet. Any ideas?

Besides the suggestion Rahul pointed to you can also use the sandbox 
command which will lock down other things as well. It is in 
policycoreutils-python. I am not sure if that is installed by default.
There is a man page for it that will describe what it limits and how 
to allow access to some things that are blocked by default.