Install second network interface on virtualized Ubuntu Server

Question

I've just installed the latest Ubuntu 16.04 on a VirtualBox machine. I'd like to have two different network interfaces:

1. the first one to access the guest machine from the host using ssh; for this reason, I've installed the Host-only Adapter as adapter 1
2. the second one to be able to connect to internet from the host machine, so I've installed a basic NAT as adapter 2

However, even if both the network adapters are correctly identified, only the first one is accessible.

$ ls /sys/class/net/
enp0s3  enp0s8  lo

$ ifconfig
enp0s3    Link encap:Ethernet  HWaddr 08:00:27:47:52:7b  
          inet addr:192.168.56.101  Bcast:192.168.56.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fe47:527b/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:399 errors:0 dropped:0 overruns:0 frame:0
          TX packets:246 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:44031 (44.0 KB)  TX bytes:75269 (75.2 KB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:92 errors:0 dropped:0 overruns:0 frame:0
          TX packets:92 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1 
          RX bytes:40721 (40.7 KB)  TX bytes:40721 (40.7 KB)

How can I make the system recognize the second card also?

Answer 1

I've solved the problem adding

# The secondary network interface
auto enp0s8
iface enp0s8 inet dhcp

to /etc/network/interfaces

and restarting the network using sudo service networking restart.

Now, here is the result of

$ ifconfig enp0s3    Link encap:Ethernet  HWaddr 08:00:27:47:52:7b  
          inet addr:192.168.56.101  Bcast:192.168.56.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fe47:527b/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:6334 errors:0 dropped:0 overruns:0 frame:0
          TX packets:7656 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:2741526 (2.7 MB)  TX bytes:10824219 (10.8 MB)

enp0s8    Link encap:Ethernet  HWaddr 08:00:27:3e:1e:bf  
          inet addr:10.0.3.15  Bcast:10.0.3.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fe3e:1ebf/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:8 errors:0 dropped:0 overruns:0 frame:0
          TX packets:16 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:1730 (1.7 KB)  TX bytes:1882 (1.8 KB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:2143 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2143 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1 
          RX bytes:443165 (443.1 KB)  TX bytes:443165 (443.1 KB)