[Solved] Bridged Adapter Works, But No Internet (DNS Problem

[concept]

Hi.

I apologise if this has been covered before, but I haven't managed to find it:

I'm running VirtualBox 3.0.10 on Windows XP Professional SP3. I've created a virtual machine and installed Windows Server 2003 Standard on it. In the virtual machine's settings, I set adapter 1 as:

Intel PRO/1000 MT Server (82545EM)
Bridged Adapter
Belkin F5D5005 v2000 Gigabit Desktop PCI Card

It all works fine. I get an IP address from my physical broadband router, on the same subnet as the rest of my network, and I can ping any physical machine on my network, by host name.

The problem is that I then can't access anything on the world wide web. If I try pinging yahoo.com for example, I get the old:

Ping request could not find host yahoo.com. Please check the name and try again.

I can ping it by IP address though, so it looks like DNS isn't working. I'm using open DNS throughout my network, because my broadband provider is having issues with DNS at the moment, and I've set the virtual machine to do the same. My pysical machines can resolve anything, but the virtual can't.

If I set the network adapter on the virtual machine as "Attached to:" NAT, then it all works fine, but I just don't like it using NAT. I want it on the very same network that everything else is on.

Does anyone have any suggestions?

Thanks.

[Perryg]

Look for firewall issues
Double check the DNS settings of the guest.

[concept]

Thanks for your reply perryg.

I don't think it's a firewall issue, as Windows Server 2003 doesn't seem to have a built-in firewall (I couldn't find it to disable it anyway) and I haven't installed one (this is a fresh install), and also because it worked when I was using NAT for the network adapter, without me making any changes to the guest OS.

It definitely seems to be something to do with DNS, but I don't know what.

Thanks.

[Perryg]

Open a command window on the guest and type nslookup
Once you are at the prompt type yahoo.com and post the window contents here
Also type ipconfig /all and post the results here.

[concept]

Thanks again:

NSLookup on guest

Win2K3 NSLookup.JPG (61.88 KiB) Viewed 22699 times

208.67.222.222 and 208.67.220.220 are the addresses I'm using for DNS. Strangely, although the guest cannot use them for a DNS lookup as shown, it can ping 208.67.222.222 no problem.

IPConfig on guest

Win2K3 IPConfig.JPG (76.59 KiB) Viewed 22700 times

I thought you might also want to see what an IPConfig looks like on the host, so here it is:

IPConfig on host

Render IPConfig.JPG (102.63 KiB) Viewed 22702 times

As for a DNS lookup on the host, I get the standard result and yahoo.com resolves to 67.215.65.132.

So can you or anyone else think of any reason why I would be able to ping the Open DNS servers (208.67.222.222) but not use them for lookups? Could it be something to do with the fact that I basically have the same NIC using two different internal IP addresses? Maybe the responses to the lookups get returned to the host and not the guest? Or am I talking rubbish?

Thanks.

[Perryg]

Something is getting filtered somewhere.
Try setting the guest to use DHCP for DNS and see if it resolves. I know you said they were having problems but they could not stay in business if it was global and did not work at all.
I need to see that you can actually get this information from your router.
Also while it should not the host firewall could be causing a problem as well as the router firewall depending on how it is setup.
Look and try disabling the firewalls on both to test and see if the guest can make it to the DNS server.
Are you using MAC filtering on the router?

[concept]

Well I never...

The firewall on the host was one of the first things I thought of, but I immediately dismissed it because I figured that as far as the guest was concerned, it was connecting directly to my router and not through the host. I also looked in my firewall's logs and it didn't report having blocked anything. Thinking about it now, it's obvious that VirtualBox has to go through the host somehow. D'oh!

So that fixed it: I disabled the firewall on the host and it worked. Now I just have to figure out what my firewall is blocking exactly, so I don't have to turn the whole thing off. But I can sort that out myself, so don't worry about that.

Thanks for all your help Perryg!

[Perryg]

Good. I will mark this topic solved.

[concept]

Okay if anyone cares, I'm using Sunbelt Personal Firewall 4 on the host. To fix this problem, I went to "Network Security" (in the firewall's console), then the "Advanced" tab, and ticked "Enable gateway mode..."

The reason the blocked connection attempts weren't showing-up in the firewall's logs was that I hadn't enabled logging of packets going to unopened ports.