Virtualbox bridged network is unreachable

Question

I'm trying use a network bridge adapter for my VM (fresh Ubuntu server 16.04 LTS install) within the latest version of Virtualbox (v5.0.20). Running ifconfig -a gives the following output:

As you can see the IP-address is 192.168.3.59, which is being assigned by the DHCP server of my host network (subnet 192.168.3). So everything seems to work just fine, but when I'm trying to ping to 8.8.8.8, for example, I get the following error message:

Connect: network is unreachable

I've tried different adapter settings, disabling the firewall, created new VM's and Googled everything I could think of; however, nothing solved the problem.

Some more information which may be useful:

• The host PC runs on Windows 10
• The interfaces (/etc/network/interfaces) file is untouched
• Using two adapters (NAT and host-only) works, but this is not what I need
• I have an old VM (Ubuntu 14.03) working just fine with the bridge adapter

Any help/suggestions would be greatly appreciated!

Edit: added routing table

ip route show outputs the following:

172.23.23.0/24 via 192.168.3.108 dev enp0s3
192.168.3.0/24 dev enp0s3 proto kernel scope link src 192.168.3.59

Solution

You're missing default route for traffic outside the scope of the subnet. Run following command as privileged user:

ip route add default via ip-of-router-on-local-network dev enp0s3

This should allow you to ping google's servers and make outside connections. Making this setting permanent (to persist after reboot) will depend on the method your VM connects, but this should work on most systems: http://www.linuxquestions.org/questions/linux-networking-3/permanently-add-static-route-16769/

Comments

[Marek Rost]

This could be routing table issue - Your VM doesn't know where to send packets destined for 8.8.8.8. Add that to the question please ( for example by pasting output of 'ip route show' )

[JasonK]

@MarekRost I've updated my answer with the routing table.

[JasonK]

You've definetly pointed me in the right direction with the routing table, thanks alot! I've ended up adding sudo ip route add default via 0.0.0.0 dev enp0s3 to etc/network/interfaces. Pretty weird that this route should be added manually, my old VM has added this route by default.

[Marek Rost]

You're welcome. I'm not sure your solution will work though . /etc/network/interfaces isn't parsed as regular shell script. And even if - sudo is unlikely to work as well, since it won't be run by your normal user. Instead try setting the GATEWAY variable in this file to your router, hopefully this will create the default route.

[JasonK]

Adding up ip route add default via 0.0.0.0 dev enp0s3 works, but setting the gateway doesn't seem to work. Another fun fact is that this problem is only occuring on Ubuntu 16.04, everything works fine on 14.04.4 LTS.

[Marek Rost]

Hmm - this could be due to Ubuntu's transition from upstart init to systemd init. In systemd static network configuration is loaded from /etc/systemd/network/<your-name>.network. Service responsible for loading these settings is systemd-networkd. Consult man page for futher details.