Let me set the stage for you: You’ve had VirtualBox virtual machines running smoothly for a long time. Your VMs have been successfully serving up your apps and/or services without fail. But then, one fateful day, your company migrates its networking scheme or moves the business entirely. Because all of your VMs are set up to use Bridged Networking, VirtualBox should continue serving up those VMs without a hitch.

But alas, that isn’t the case. All of a sudden things aren’t working as planned. Although the VMs seem to be able to reach both the LAN and WAN, no one in your company can reach any of the VMs. What’s happening?

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Oddly enough, something very simple, but it’s an issue that might trip you up. No matter what you do with the network configurations within the VMs, nothing will change. Why? Because the issue is with VirtualBox, not the individual VMs.

Fortunately, I have the fix for you, and it’s one that’ll have you shaking your head that you didn’t see it (because it’s right there, mocking you with impunity).

It’s time you knew the fix.

The fix

Here goes.

Unfortunately, you must fix this on a per-VM basis (there is no global fix for the problem). Open VirtualBox, select one of the virtual machines, and click Settings. Click on the Network tab, and you should see your adapter is still set to Bridged (Figure A).

Notice the Name setting. This was the name associated with the adapter in the previous LAN setup. That’s the culprit. You see, that named adapter retains information from your previous network. Even if you change providers, and your internal network scheme remains the same, you might find that named adapter won’t allow traffic into the VM. What do you do?

Click the Name dropdown. You should see a brand new name (that didn’t previously exist) listed (Figure B).

Select that new adapter name and click OK. Once you do that, either start or restart the VM. When the virtual machine boots, you should now be able to reach it without a problem.

Simple problem, simple solution

This is one of those issues that may have confounded you for days. Fortunately, it’s a simple problem with a simple solution. The alternative being, you wind up having to re-install all those VMs, and no admin wants to go through that.