Virtual Box Guest Additions on Fedora 13 installation guide:

Before installing guest additions on fedora 13 make sure that following packages are installed on your fedora 13 virtual machine.

1. make
2. automake
3. gcc
4. gcc-c++
5. dkms
6. kernel-headers
7. kernel-devel

you can inquire your system for above packages using this command:

Virtual Box Bridged Networking:

Bridged Networking:

In bridged networking Virtual box uses a software driver interface on the host machine that enables the virtual machines to get their IP addresses from the same source to which the physical interface of the host system is connected. When connected this way guest machines see themselves as they are physically connected to the host through a wired connection.

Linux Mint Isadora on Virtual Box installation with guest additions:

About Virtual Box and Virtual Machines:
Virtual box is a virtualization software that provides a lot of features and support for creation and installation of virtual machines .A virtual machine in every aspect is comparable to your real hardware compartment(cpu box) ,the only difference is that you just can't touch it.
In simpler words it has its own RAM ,Hard Disk,Network cards,Video capabilities ,Audio ,and processing . Actually it is an abstract layer of hardware provided by a virtuallization software, so when we run an operating system inside a virtual machine it only sees this layer as its hardware regardless of what your real hardware is.