Solve “connect: Network is unreachable” issue with VirtualBox

Hello,

Today, I had a very annoying problem with VirtualBox: network hardly ever works, but sometimes it works and I can’t know why… It’s very strange. I found a solution when it doesn’t work. If I do on the VM:

> sudo ifconfig
eth0      Link encap:Ethernet  HWaddr 08:00:27:87:e5:ec  
          inet6 addr: fe80::a00:27ff:fe87:e5ec/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:73 errors:0 dropped:0 overruns:0 frame:0
          TX packets:93 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:10049 (9.8 KiB)  TX bytes:8638 (8.4 KiB)
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:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

I can see that strangely I don’t have an IPv4 address. So it means that I’m not able to connect to internet. We can easily verify this:

> ping [An IP of Google]
connect: Network is unreachable

So my solution is simply to restart networking service until ifconfig show an IPv4 address:

> sudo service networking restart

So we do:

> sudo ifconfig
eth0      Link encap:Ethernet  HWaddr 08:00:27:87:e5:ec  
          inet addr:10.0.2.15  Bcast:10.0.2.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fe87:e5ec/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:237 errors:0 dropped:0 overruns:0 frame:0
          TX packets:234 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:27938 (27.2 KiB)  TX bytes:23963 (23.4 KiB)
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:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

If ifconfig show an IPv4 address like here, everythings is OK. If not, restart networking service again.

Thanks for reading!