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HowTo Configure VirtualBox

Introduction

VirtualBox is a great product for virtualization and it works pretty well for openchangesim purposes. However it requires a few modifications on Microsoft Windows operating systems in order to manage properly hundreds or thousands or concurrent MAPI communications. The following instructions apply for VirtualBox (3.2.8), are probably valid for anterior versions and may probably remain valid unless this bug is fixed.

Problematic

If your virtual machine is using a bridged interface directly linked to a physical interface, then openchangesim will probably fail running with 10 concurrent users. One potential reason is that the VirtualBox bridge code fail to handle all the incoming traffic from physical interface, leading in some IP stack overflow which prevent from any further communication to the virtual host. The following instructions intend to fix this issue.

Creating a MAC bridge Miniport

What we will do is put our physical interface within a MAC bridge and use this bridge as the bridged interface our virtual machine needs to rely on.

To create a MAC bridge Miniport:
  • Click on Start > Control Panel and select network interfaces
  • Right click on the network interface you used along with the virtual bridged interface
  • Select the "Bridge Connections" option in the menu
  • After few moments, Network Bridge should be created and activated by Windows
  • Check for IPv4 options on this new interface and check if it has an IPv4 address assigned

Using the MAC bridge Miniport in VirtualBox

In VirtualBox, shutdown the virtual machine, then:
  • Select the virtual machine in the GUI
  • Click on Settings
  • Select Network in the left menu
  • Look within the tabs for your bridged interface (generally Adapter 1 or Adapter 2)
  • In the Adapter pane, use the drop-down list associated to the Name item and select MAC bridge Miniport
  • Valid your choice by clicking on OK
  • Start the virtual machine again

Your virtual machine should now work properly and able to handle hundreds of simultaneous communications.