Hello there

There are two Debian VMs in my Oracle VM Virtual Box.
I would like to set up a network in order to make them "pingable" among themselves. Webpages such as google.com should be "pingable" too.
How do I have to set up the network environment?

Here are two screenshots:

Screenshot1
Screenshot2

I have tried to bridge the wifi and the VirtualBox Host-Only Ethernet Adapter. ping google.com delivers a unknown host and ping vm delivers a Destination Host Unreachable.

Anyone help please?

Thx,
Troix

Hi there,

Welcome to LQ!

I don't have a Debian insstall handy, but am guessing the screenshots are from the network config inside the VMs? If so, why is the bridge required - why not just configure the IPs directly onto the "wired" (virtual ethernet) interfaces?

What does the VirtualBox network settings look like? There are various network modes (see https://www.virtualbox.org/manual/ch06.html). The default is NAT, but what you probably want is Bridged networking. This will bridge the adapter in the VM to an adapter in the guest OS, and allow access to other VMs as well as the outside world. NAT, on the other hand, allows access to the outside, but not to other VMs.

One problem with your config might be the IP addresses. The two VMs seem to be on different subnets. Unless you have specific routing table entries to deal with this, they would not know how to reach each other, and will try to route traffic out onto the internet instead if only a default gateway is configured. Assuming you have an external DHCP server running (likely on your router), in Bridged mode the VMs should pick up IPs and other settings (gateway, DNS) from there, and end up on the same subnet as the host, which will solve your routing problem as well as the DNS problem which is most likely causing the "unknown host" error.

Good luck!

1 members found this post helpful.

your bridge cannot be connecting properly. this is a photo of VirtualBox and my client pinging to google with bridge connection to my wifi on my laptop.

Make sure you are selecting the proper connection to your box. I don't know if you did or not. But it usually defaults to the right one.

There is another showing Solaris 11.3 pining my Void Linux, they both are VM clients.

if you have a wifi and a Network card installed. it maybe choosing the wrong one, and like @cliffordw said your Default route for both clients are different.

your VM setup for bridge looks different then mine too. what up with that?
what version are you running? Just wondering. Mine is ver 5.

Attached Thumbnails

   

1 members found this post helpful.

Thx for your help!

So how do I set up two vms as hosts and one vm as a router?

vm a:
eth1: 192.168.0.44/24
default gateway: 192.168.0.100/24

vm b:
eth1: 172.20.20.44/24
default gateway: 172.20.30.100/24

vm c:
eth1:192.168.0.100/24
eth2: 172.20.30.100/24

Thx in advance,
Troix

Hi Troix,

You're a little vague on details. I'll make some assumptions, though, namely:

1. The networks in VirtualBox are set up to allow this traffic flow, and
2. VM C has a route to the destination (internet??)
3. There's no firewall rules on VM C that will block the traffic

The IP config on VMs A and B seems fine.
On VM C, if you want to route only between these VMs, you need to enable IP forwarding ("echo 1 > /proc/sys/net/ipv4/conf/all/forwarding"). If you want to route to other subnets or to public IP addresses (the internet) via VM C, you will need to either run NAT on that VM, or ensure your router knows the route back to the source addresses (on VM A & B).

I hope this helps.

1 members found this post helpful.

I agree not information on how you want your VMs configured. What operating systems are running on the VMs?

It looks like VM A network is configured as a bridge instead of host only and your host only network for VM b and c is not on the same subnet (172.20.20. and 172.20.30.).

You also need to add firewall rules for VM c to be a NAT for the other two.

1 members found this post helpful.

take this what you wrote
then go to youtube and paste that into the search bar, I got numerous hits on how tos
that might help you out, so you can see what they are doing as well.


What Is A Oracle VM VirtualBox Host-Only Network Adapter?


How to Setup Nat Network and Port Forwarding Virtualbox

How to configure internal network in VirtualBox

1 members found this post helpful.

Edit: nevermind.

1 members found this post helpful.

hello again!

Thank you for your kind help.
Another question: When using nmtui I can activate eth0 or eth1 but not both.
How do I activate both?

Thx,
Troix

my vbox has tabs in network to do more then one... try that .??

1 members found this post helpful.

Okay, so I have added a second adapter.
I can ping vm1 to vm3 and vice versa.
I am not able to ping vm2 and vm3 and vice versa.
In both directions I get a DHU.
I have activated both Ethernet Connection 1 and 2.

The screenshots are as follows:
vm1 = debian1
vm2 = debian2
vm3 settings for vm1 = debian31
vm3 settings for vm2 = debian32

thx,
troix

Attached Thumbnails

       

That is an alias not a second adapter. I've never tried using an alias with a virtual adapter yet. The two adapters on vm3 are on the same subnet and vm1 and vm 2 are still on different subnets.

How are the network adapters configured in virtualbox manager? bridged, NAT, etc.

Lets clarify your requirements again. To be pingable among themselves and still ping the outside world can be configured in several ways. Each VM has two virtual adapters i.e 1 as NAT and 2 as host only.

With VM 3 as a router mode so it has 2 virtual adpaters with vm 1 as bridged and vm 2 as host only. The other two as host only. You then configure VM 3's firewall to forward from host only port to bridged.

Lets try the first option. Go back and configure the VMs for DHCP. Configure the two virtual adapters in VBox manager as NAT and host only.

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This might help you a little bit there ye'.

how to configure linux vm as router which communicate between two subnets

this person is using a Debian set up to explain how to do this to that asker, dude in that post.

1 members found this post helpful.

hello again

I have followed the instructions from the link I have received:
http://serverfault.com/questions/613...en-two-subnets

In all three VMs I have added the information according to the content of the webpage.

Pinging between VM c and VM a works fine.
Pinging between VM c and VM b doesn't work.

I have cloned VM a to VM b and changed the ip and gateway.

Unfortunately pinging doesn't work (pinging the outside world works fine).

rc.local:

modprobe ipt_conntrack
modprobe ip_conntrack
modprobe ip_conntrack_ftp
modprobe ip_nat_ftp
modprobe ip_conntrack_irc
modprobe ip_nat_irc
modprobe ip_nat_snmp_basic


iptables -t nat -A POSTROUTING -o eth5 -j SNAT --to-source 192.168.0.100
iptables -t nat -A POSTROUTING -o eth6 -j SNAT --to-source 172.20.30.100




Thx,
Troix

How is, or why is your gateways all becoming different? that is what I remember seeing .. and is causing the problem. Even though you say you've changed them. Hum..

If I get some time .. I'll try to set up the same thing in my VBox with completely different Linux OS's and maybe try to use my Solaris I already have installed on it.

but you are using Debian for everyone of them yes?
So Maybe I'll use (cough,cough) Debian for everything and toss in Solairs for good measure.

then if I go to that link you provide and use that then see what I see. then post back (if I get time to do this) I will.

what is your two Debian and Oracle VM Virtual Box Versions for each SO I can try to imitate everything you have. my Hardware should not matter because the others are being simulated via VBox (VM). My VM version is 5.x. the kernel ver should not matter either. so that is a no big deal.

just versions of Debain and VM you are using so I can download the Debain iso's

I only have wifi at my disposal so that may be a hindrance.