DNS Access

Discussions about using Windows guests in VirtualBox.
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RTurske
Posts: 2
Joined: 30. Nov 2018, 15:27

DNS Access

Post by RTurske »

OK, so I normally don't post in forums much, but this one caught me off guard so I want to explain what happen so it doesn't catch anyone else.

I have a member server that is starting to have issues. So I decided to start doing testing with VirtualBox so I could load the server into a VM. Got everything installed, setup the NAT (without DHCP) network, and loaded a test server first. Everything went as expected. Then I setup a test workstation. Everything went fine.

The problem started when I created a VHD image of the original server that was failing. I setup the VM and booted the server. It booted fine and I was able to log on to it. It did the normal finding devices like it should, and it setup the new NIC card and pulled a DHCP address. The old physical server was static. Didn't really care since it was a test.

About 10 minutes later I got a call from my warehouse manager saying he could no longer run his software. It's backend is a SQL database on the for mentioned server.

So the issue was, the new VM server overwrote the DNS record for the physical server in the domain DNS. So the warehouse software was looking at the new VM server IP address instead of the physical server. I would not expect this to happen through the NAT, but since the VM machine does have rights to the DNS being a member server of the domain, I guess this could happen.

Anyone else see something like this? Is this expected behavior?
Martin
Volunteer
Posts: 2560
Joined: 30. May 2007, 18:05
Primary OS: Fedora other
VBox Version: PUEL
Guest OSses: XP, Win7, Win10, Linux, OS/2

Re: DNS Access

Post by Martin »

As VirtualBox doesn't have its own DNS servoce the guests are using your normal DNS servers also through NAT.
So when you start virtual system with the same name as another system on your network and it is configured to register its address on DNS then this is expected normal behaviour.
RTurske
Posts: 2
Joined: 30. Nov 2018, 15:27

Re: DNS Access

Post by RTurske »

Thanks Martin - I did see that it uses our DNS. I just didn't expect it to be able to write a record... Just caught me off guard.
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