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Adding the second networking interface

Ubuntu Server 16.04:

Modify /etc/network/interfaces. and add the following code to it:

   auto enp0s8
   iface enp0s8 inet dhcp

Older Ubuntu Versions:

Modify /etc/network/interfaces. You should have two network interfaces (eth0 and eth1 where one is the NAT interface and the other one the vboxnet0 interface), but only one has been configured by the Ubuntu installer. Assuming eth1 is the vboxnet0 interface, the file should contain these contents:
    
    ...
    auto eth0
    auto eth1
    iface eth0 inet dhcp
    iface eth1 inet static
    address 192.168.56.101
    netmask 255.255.255.0
   

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