MacOS – Mac OS X in VirtualBox Setup Guide

VirtualBox can't currently run OS X, but is slowly moving in the right direction. Version 3.1 has EFI support, which would be the first requirement for running vanilla (non-hacked) OS X Server as a guest. Keep an eye on this topic in the forums for updates.

VMware can, with some fiddling, run recent OSx86 (hackintosh) distros. VirtualBox can apparently just about run an out-of-date Deadmoo hack, but it's probably not worth it for testing software on OS X as the results are very unstable.

Independent of firewalls or other considerations, there are two basic ways gain access to a VirtualBox VM Guest hosting e.g. a web server.

The first option is to add a bridged network adapter (this is the simplest solution). This will add a virtual adapter for the Guest that can be accessed like any normal machine on the network (i.e. via a discrete local IP address ex. assigned by your router's DHCP).

The second option is to use the existing NAT adapter's Advanced options to configure port forwarding, like you would on a router. That is, you would take e.g. port 80, and tell VirtualBox to pass requests for that port to your Guest.