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Then start VirtualBox and create three new VMs, using 2 GB memory each and choose to point them to an existing harddrive file (you will need to "add" the VMDK files you copied earlier to the "Virtual media manager" in VirtualBox). After creating the new VMs, we need to configure the network adapters. Before we can do this go into the menu  File→Host network manager File→Tools→Network Manager... in VirtualBox and create a new network called vboxnet1 for example, and enter IP 10.100.2.2 / 255.255.255.0 (no DHCP server). On Linux/MAC you need to allow this IP-range in by creating /etc/vbox/networks.conf and specifying allowed ranges there. For example, to allow 10.0.0.0/8 and 192.168.0.0/16 IPv4 ranges as well as 2001::/64 range put the following lines into /etc/vbox/networks.conf:

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