He cannot go out and is therefore secure inside.
A sandbox in computer terms works pretty much the same way.
The app needs to inform the sandbox before beginning execution which resources it will need.
Why is this used ?
To ensure an desktop software or a Mobile App/website doesnt perform any action it is not supposed to.
Sandboxing such kind of tool also certifies that it is indeed containing malicious payload.
FortiSandbox-VM
The salient features of FortiSandbox-VM is that it ties up with the other products provided by Fortinet.
FortiSandbox-VM features a dual-level sandbox with inspection of all protocols and functions in one appliance.
source: www.techworm.net