setup the guest network in KVM to interact with the outside world (google.com )

Question

I am trying to better understand the network setup in my machine.

Host Machine Setup

1. I have a wireless interface (wlan0) on my host machine which has the IP address as 192.168.1.9.
2. The default gateway of this host is the router which goes to the outside world through my ISP, whose IP address is 192.168.1.1.

3. The route -n command in my host machine returns me the output as,

   Kernel IP routing table
   Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
   0.0.0.0         192.168.1.1     0.0.0.0         UG    0      0        0 wlan0
   169.254.0.0     0.0.0.0         255.255.0.0     U     1000   0        0 wlan0
   192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 wlan0
   192.168.1.160   0.0.0.0         255.255.255.224 U     0      0        0 virbr2
   

Guest Machine Setup

Now, I setup a guest OS in KVM as below.

1. The KVM is in a sub-network which has the details as 192.168.1.160/27.
2. The DHCP start is 192.168.1.176 and the DHCP end is 192.168.1.190.

3. I also did the below command for my KVM configuration to work.

   arp -i wlan0 -Ds 192.168.1.9 wlan0 pub
   

From the guest OS, I see that my IP address is 192.168.1.179. My route -n command in the guest machine returns me the output as,

kernel IP routing table
Destination     Gateway         Genmask
0.0.0.0        192.168.1.161    0.0.0.0
192.168.1.160  0.0.0.0          255.255.255.224

How can I make the guest OS to interact with the outside world?

EDIT

This is the output of virsh net-list --all.

ramesh@ramesh-pc:~$ virsh net-list --all
 Name                 State      Autostart     Persistent
----------------------------------------------------------
 arpbr0               inactive   yes           yes
 default              active     yes           yes
 proxyArp             active     yes           yes

Answer 1

I would like to thank user slm for guiding me in the right direction in setting up the guest network in the KVM. I will add the screen shots to the answer so that it will be more informative.

I assume the virt-manager package is installed and also the host machine is setup with the necessary packages for KVM to work.

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Preparing the Network For Guest to Host Interaction

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The main step in the KVM is setting up of the network. If the machine is not available in the network, then it serves no purpose, be it physical or virtual.

Type virt-manager in the terminal. The console would show up as below.

Click on Edit -> Connection Details and a new screen would pop up as below.

Click on Virtual Networks tab and from there click on the + button to add a new network to the KVM guests.

Click on Forward and then we would be presented with the below screen. Now, the IPV4 addresses we choose here is completely up to our choice and we could optimize this step to suit our actual needs.

After we click on Forward in the above screen, we would be presented with the below screen. In this step, it basically tells the address space available for us.

In this step, choose forwarding to physical network and select the host's network interface which will help the guests to interact with the outside world.

After the above step, we are almost done and we just would be presented with the below screen, which is kind of a review of all the details we chose so far.

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Adding this new device to our Guest OS

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From the initial screen of virt-manager, click on the Open and we will be presented with a screen as below.

From the above screen, click on the i to open up another screen as below.

Click on Add Hardware and select Network. In the Network tab, select the host device as our newly created network in the previous step and click on Finish as shown in the below screen.

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Testing in the guest OS

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Now, inside the guest OS make sure that you are able to ping the host machine and outside network such as google. If the ping succeeds, then we have successfully setup our network in the guest OS.

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References

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The reference material used to setup the guest network

Answer 2

setup static routes in your router(192.168.1.1).

# ip route add 192.168.1.160/27 via 192.168.1.9 dev < wlan iface>

or via webui.

add iptables forward routes on your host from router to 192.168.1.160/27 and vice versa (although, i think, libvirt provides these rules already).