NAT Network provides connectivity between VMs but not to the outside world.

[Sakis Hrist]

System Information:

• Linux Mint 19
• VirtualBox 5.2.10_Ubuntu r121806
• Installed VirtualBox Extension Pack 5.2.16r123759

Description of the issue:

I have created a NAT Network with the following parameters:

Name:        RHCE original
Network:     192.168.4.0/24
Gateway:     192.168.4.1
IPv6:        No
Enabled:     Yes

And DHCP:

NetworkName:    RHCE original
IP:             192.168.4.3
NetworkMask:    255.255.255.0
lowerIPAddress: 192.168.4.4
upperIPAddress: 192.168.4.254
Enabled:        Yes

I have two VMs like so:

VM1: 192.168.4.210/24
VM2: 192.168.4.4/24

The DHCP works as expected and networking between the VMs seems to work fine. What does not work is access to the outside, including access to the gateway. I have tried this on another machine as well and it does not work as well.

Notes:

• NAT (not NAT Network) works properly.
• No additional interface or bridge on the host is created when the network is created/started (probably this is OK, but I though it worth mentioning)

Expected behavior:

Being able to perform ping 8.8.8.8 from the guests and to return a reply.

Attached files

• VBoxSVC.log while starting the VM
• VBox.log from the VM
• tcpdump from while performing ping 8.8.8.8

[Mihai Hanor]

The VBox.log shows that you're using a Host-only Adapter setting, not NAT Network, for your guest. It's expected not to have any external network access.

[Valery Ushakov]

Indeed, you are not using NAT Network.

If the log was somehow wrong, please, reopen with new information.

[Sakis Hrist]

Sorry, aparetnly I have attached the log from the session I ran with host-only net for getting the pcap file out of the box. Let me attach again...

[Sakis Hrist]

Please refer to the newly added VBox.2.log

Thanks for pointing it out.

[Socratis]

VirtualBox VM 5.2.10_Ubuntu r121806 linux.amd64 (Jun 15 2018 16:14:07) release log

That's the Ubuntu fork, and a rather old one. You can either ask in their forums for help, or completely remove/uninstall/delete/purge their version and install the official version from the Downloads section of VirtualBox.

00:00:00.511318 File system of '/home/sakis/VirtualBox VMs/server1/server1_3.0-disk1.vmdk' is ext4
00:00:00.513484 File system of '/home/sakis/VirtualBox VMs/server1/server1_3.0-disk2.vmdk' is ext4
00:00:00.530982 [/Devices/lsilogicscsi/0/] (level 3)

You did not create this VM yourself, did you? You imported that VM. As such, have you checked that the TCP/IP settings are appropriate? Have you tried with a Live DVD and that failed? If you haven't please do.

BTW, it's usually better and faster, if issues get first addressed in the ​VirtualBox forums. More than 95% of the issues are resolved over there, which keeps the developers focusing on the bug fixes and enhancements, and there is no need for another ticket to keep track of.

So, if you can, please open a new thread in the ​Using VirtualBox section of the forums. Please be sure to mention that you came from the bug tracker and include the ticket number.

[Mihai Hanor]

What's your host's network address?

[Valery Ushakov]

But the pcap was captured with NAT Network, right?

[Valery Ushakov]

There's also a log file for the nat network in ~/.config/VirtualBox/$natnet.log. Not much there usually, but it lists the MAC and IP it uses.

[Sakis Hrist]

OK, hate to admit, but apparently I've messed up with the versions.

Yes, this is the official Ubuntu version. I thought that by adding the PPA and installing virtualbox would get me the latest version. I had to install virtualbox-5.2 instead. Since I installed that, the issue described here does not exist, and the NAT network works as intended.

So I guess there's no need to answer the rest of your comments.

Sorry for taking your time people, and thanks for pointing out the obvious for me.

Can be closed.

[Valery Ushakov]

Thanks for the update