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I am trying to get the bridge network connection to work on my Ubuntu 12.04 VirtualBox running on my Mac OS X 10.6.8 through the AirPort.

Using NAT with AirPort works fine, and using bridge to ethernet works fine, but bridging using AirPort causes the Ubuntu guest's network icon to simply spin (I think it is trying to get an IP through DHCP) and never connects.

I want to be able to run Epoptes teacher console in the guest Ubuntu 12.04 and connect to several Ubuntu 12.04 laptops in my classroom (yes, I'm a teacher). I have successfully setup Epoptes to work on a wired computer lab where to teacher computer is running Ubuntu 12.04 natively. I want to replicate this but use an Ubuntu VirtualBox on a Mac laptop. This does not seem to work using NAT network connection on the VirtualBox. Please help!

To explain briefly what NAT & Bridged is (you will find more details into the User Manual) :

Bridged is like having another computer on your network, the VM will appear like a regular extra hardware machine, and the same rules will apply to it as any other machine connected to that network.
By that, I mean that you will need to assign a static IP if there is no DHCP server available, make sure there are no port security where you are trying to connect (or modify it to allow it to work), router should be aware if a port forwarding is required, etc.

NAT is like (very very simple view of it) transforming your host into a half router, half proxy. The VM will have its own network, not reachable from the host, and any request to the outside world will be translated by the Virtualbox executable and anything coming out from the VM will appear as it came from the host.
The issue with NAT is that, just like other routed mode, you will need to configure port forwarding if your application acts like a server. You will then need to know which port, is it UDP or TCP.

You are trying to use AirPort but AirPort is a host feature, built into OSX. what you need to use is a real NIC. Whichever mode will depend on your requirements

Thank you for your reply, noteirak! I was trying to get this to work at my school for the past 2 days. I am now at my friends house and just tried it again. I understand the differences between NAT and bridging a little better now. I was trying to bridge using my AirPort with no success at school. At school we have a proxy server. At my friends house, I can used a bridged connection to the AirPort with no problem! It seems that my proxy server was not allowing the guest Ubuntu OS to have a DHCP IP address, very annoying!! So my virtualbox set up works great without a proxy server. Do you have any suggestions when doing this all behind a proxy server?

I assume it is a HTTP proxy server.
If so, the configuration of a real machine would apply here too : you need to indicate the proxy server either in your guest OS or in the programs running on the guest OS if they have their specific proxy configuration.
All these are specifics to the guest OS & your application, so not much more can be said

KMack1 wrote:Thank you for your reply, noteirak! I was trying to get this to work at my school for the past 2 days. I am now at my friends house and just tried it again. I understand the differences between NAT and bridging a little better now. I was trying to bridge using my AirPort with no success at school. At school we have a proxy server. At my friends house, I can used a bridged connection to the AirPort with no problem! It seems that my proxy server was not allowing the guest Ubuntu OS to have a DHCP IP address, very annoying!! So my virtualbox set up works great without a proxy server. Do you have any suggestions when doing this all behind a proxy server?

DHCP and a proxy server don't have much in common. If a machine cannot get an IP from DHCP, it has nothing to do with a proxy server.

A proxy server allows a client access to the Internet. It is quite different from NAT. With NAT, the client thinks that it has an Internet connection and NAT looks after the complications. It is invisible to the client OS. With a proxy server the client must know what the IP address of the proxy server is. The vm would need to have the proxy server client software installed and have the address of the proxy server configured somewhere, just as the host does.