FreeBSD Internet in VirtualBox

Set up the bridge network:
The advantage of bridge network in Virtualbox is that, Virtualbox can been seen by the outside world, not just your host. One practical example of this use is that you can set out a server using Virtualbox. With bridging your virtualbox is assigned with an IP address in your network (same network as your host).

In FreeBSD, you need drives to use bridging in VirtualBox:

kldload vboxnetflt vboxnetadp
or
vboxnet_enable="YES" in your /etc/rc.conf

and then go to your Virtualbox settings, try bridge to your host Interface(NIC)

Manually configure your virtual network:
You can easily set up FreeBSD Internet under VirtualBox. To troubleshoot, manually configure your network interface as follow:

1. Check your DNS: 10.0.2.3 ( i.e. modify your /etc/resolv.conf)
2. Check your IP: 10.0.2.15 ( e.g. ifconfig em0 inet 10.0.2.15)
3. Check your default gateway: 10.0.2.2 ( i.e. route add default 10.0.2.2)