Simple networking: Hyper-V Internal Virtual Switch on Windows 8.1

Question

I am running Windows 8.1. I have downloaded Windows Vista VM for IE7 testing from http://modern.ie

I also have VirtualBox installed to use with vagrant. Since Hyper-V is not yet supported by vagrant.

When I create a virtual machine with VirtualBox, the default network configuration do the following:

• Webserver running on host can be accessed by guest and vice versa.
• Both host and guest OS can be accessed via the Internet.

When I create a virtual machine with Hyper-V and assign External network, the following happens:

• The host looses its Internet connectivity
• Guest gets connected to the Internet.
• Webserver running on host is not accessible on guest.

When I assign to the Internal network and in physical Ethernet connection property I share Internet connection with vEthernet Hyper-V's connection on host, the following transpires:

• Host is connected to the Internet.
• Webserver running on host is not accessible on guest.
• Guest has not Internet connectivity.

Questions:

1. How to mimic the default behavior of VirtualBox in Hyper-V? That is; make both guest and host connected to Internet as well as internally.
2. Is it an abnormal behavior happening due to VirtualBox installation? Some kind of a conflict?

I tried Hyper-V on several other machines running Windows 8 in past. But I am never able to get the Hyper-V networking straight.