It’s not always enough to have only one virtual machine for testing purposes. More – it’s not enough in most of the cases. One of such cases is – for example – when you want to try a multi-node configuration for software like Hadoop or Cassandra, or make a failover test of your system. For me most comfortable and useful is to have a configuration that allows guest system to use the Internet (usually it’s a default, NAT mode) but also makes it possible to easily connect to guest system from host system (not by port forwarding) and makes guest systems able to “talk” with each other – it’s good enough to mimic most of production configurations I use. To do this we need to setup a two-network-cards configuration for alle the guest systems we have. This article is about how to make it work.