Virtual labs ??

Hey All

I been beating my head with self studying and experimenting linux hoping to go for a cert in the future. So i figured practicing on virtual labs can be beneficial.
I have installed VirtualBox on my laptop and have OpenSuse running on it, I am trying to install FreeBSD too, but I feel limited when it comes to networking

Does anyone here have any experience with virtual labs? any references or alternatives?

Please refer http://fabrice.bellard.free.fr/qemu/about.html

QEMU is very simple to setup and use, when it comes to emulation and virtualization.