Networking with VirtualBox
Network Address Translation
NAT mode gives you a quick and uncomplicated approach to breaking out of jail. After selecting NAT mode in the Connected to drop-down box, the virtual network card is assigned an address by a simulated DHCP server with a firewall that gives the virtual machine access to the outside world.
Figure 3 shows you how this works. In step one, the adapter in the virtual machine is automatically assigned an IP address by the integrated DHCP server, which normally assigns addresses in the 10.0.x.x. range.
As soon as the guest starts transmitting packets over the virtual wire, VirtualBox captures the packages and inserts the host system's IP address before sending them onto the Internet.
Although the configuration does not take long, this operating mode involves one functional drawback: IP address implementation (NAT) in combination with the internal firewall lets the guest system send data out into the world; however, the outside world, and the host, are kept out. The only exception here is remote desktop in the commercial version, or you can use VPN tools such as Openvpn to tunnel into the box.
Port Forwarding
In other words, it is impossible to encapsulate production servers in the virtual NAT machine in a meaningful way. Port forwarding gives you a workaround. VirtualBox listens on a port on the host system and forwards packages arriving at this port to a port on the selected virtual machine. From another machine's point of view, it seems that the service is available directly on the host.
Three VBoxManage commands enable port forwarding before launching the virtual machine:
VBoxManage setextradata "UbuntuVM" "VBoxInternal/Devices/pcnet/0/LUN#0/Config/myservice/Protocol" TCP VBoxManage setextradata "UbuntuVM" "VBoxInternal/Devices/pcnet/0/LUN#0/Config/myservice/GuestPort" 22 VBoxManage setextradata "UbuntuVM" "VBoxInternal/Devices/pcnet/0/LUN#0/Config/myservice/HostPort" 2222
This tells VirtualBox to forward all TCP connections for port 2222 on the host to port 22 on the guest. myservice is a freely assignable name, and UbuntuVM is the name of the virtual machine. If all of these values are empty when the command is called, VirtualBox will disable port forwarding again.
Host Interface
NAT with port forwarding entails noticeable organizational overhead. The administrator must open – and possibly secure – ports on the server; of course, you need to keep track of which ports are mapped to which services on which machine. Host Interface Networking mode gives you a more convenient approach to running a server on VirtualBox, although setting up this mode is quite tricky.
In Host Interface Networking mode, VirtualBox creates an additional virtual network card on the host – for example, vbox0 besides the familiar eth0. After setting up the new network card, VirtualBox uses a virtual cable to patch the connection to the simulated adapter on the guest system (Figure 4).
For productive applications, VirtualBox typically uses a bridge to connect the physical and virtual networks. This union acts like a single large network in interactions with the outside world.
To set this up, you first need to set up a virtual network interface for each guest on the host.
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
Juno Computers Launches Another Linux Laptop
If you're looking for a powerhouse laptop that runs Ubuntu, the Juno Computers Neptune 17 v6 should be on your radar.
-
ZorinOS 17.1 Released, Includes Improved Windows App Support
If you need or desire to run Windows applications on Linux, there's one distribution intent on making that easier for you and its new release further improves that feature.
-
Linux Market Share Surpasses 4% for the First Time
Look out Windows and macOS, Linux is on the rise and has even topped ChromeOS to become the fourth most widely used OS around the globe.
-
KDE’s Plasma 6 Officially Available
KDE’s Plasma 6.0 "Megarelease" has happened, and it's brimming with new features, polish, and performance.
-
Latest Version of Tails Unleashed
Tails 6.0 is based on Debian 12 and includes GNOME 43.
-
KDE Announces New Slimbook V with Plenty of Power and KDE’s Plasma 6
If you're a fan of KDE Plasma, you'll be thrilled to hear they've announced a new Slimbook with an AMD CPU and the latest version of KDE Plasma desktop.
-
Monthly Sponsorship Includes Early Access to elementary OS 8
If you want to get a glimpse of what's in the pipeline for elementary OS 8, just set up a monthly sponsorship to help fund its continued existence.
-
DebConf24 to be Held in South Korea
Busan will be the location of the latest DebConf running July 28 through August 4
-
Fedora Unleashes Atomic Desktops
Fedora has combined its solid distribution with rpm-ostree system to make it possible to deliver a new family of Fedora spins, called Fedora Atomic Desktops.
-
Bootloader Vulnerability Affects Nearly All Linux Distributions
The developers of shim have released a version to fix numerous security flaws, including one that could enable remote control execution of malicious code under certain circumstances.