Well, in my personal case, I had a similar problem with the virtual machine configuration. Nevertheless, when you know the concepts is an essay task to choose your ideal parameters.
I want to describe the different possibilities to config the virtual machine (with Virtual Box), these alternatives were tested by me.
[ul]Nat: Your virtual machine has Internet (your computer/server give Internet to the virtual machine), own network in the virtual machine.[/ul]
[ul]Nat (redirection port): Your virtual machine has Internet (your computer/server give Internet to the virtual machine), own network in the virtual machine but now, the request that your computer/server receives, these will redirect to your virtual machine (you have to select both ports). [/ul]
[ul]Host only adapter: Your virtual machine stays in a private network, you can access with your computer/server without kind of issue. Although you have not Internet.[/ul]
Probably these doubts are quite easy to find their solution but if you know what problems can generate SciDB, you will anticipate to them.