Access VM via static IP (NAT?)

Question

Machine 62: Ubuntu 16.04, has access to internet, can be accessed via the internet. On the 62 machine, there is VirtualBox with a VM (also Ubuntu).

I'd like the VM to behave like a 'normal' machine (ip-requests). I reserved a static IP for it, but now I'm not sure how to configure the interfaces of the host and the guest in a way I can ping the guest-machine like I would usually ping the host machine (via the reserved IP instead of 62...).

ReverseProxy worked for a while, but then I needed websockets over ports I don't know in advance. So now my next guess is NAT? ipforwarding? Bridged networks? Masquerading?

Answer 1

You've to create a bridged network between the Host and VM. The configuration varies on Hypervisor vendor.

In case you're using Oracle Virtual Box

1. Open Oracle VM VirtualBox Manager, select the VM and go to network section.
2. In Adopter 1 tab change the default NAT to Bridged Adopter and chose host's Network Adopter from Name drop-down. Apply it.
3. Now configure network inside VirtualBox as per your ISP's configuration like static dynamic etc.

If you're using QEMU-KVM

1. Open Virtual Machine Manager GUI tool (In case you're using GUI)
2. Select the specific Virtual machine and Open it. Then select the NIC
3. Chnage default NAT to Host Device xxxxxx: macvtap apply and then configure network inside Virtual Machine as per ISP's configuration.
4. If you don't have GUI tool then use virsh edit virtual-machine-name and modify the configuration as described previously.

A third alternate is creating iptable NAT rule in host. Then forward all traffic towards that IP (which you want to assign to VM) to VM's internal IP address. You've to write a few iptables line, please google for it. But for me it's the least preferred method.

NOTE-1 Bridged Network and macvtap doesn't work with most of the WiFi adopters in host.

NOTE-2 In case of macvtap your host will be unreachable from VM and vice versa. Both of them will be reachable from outside network. Further, if you've multiple VM they will remain reachable to each other. This is the way macvtap works. To access VM's from host and vice versa create one more NAT adopter in case of Oracle VirtualBox and one more NIC with NAT for QEMU-KVM.

NOTE-3 For both Bridged Network and macvtap the host's network adopter must have an IP address reserved per VM, as the question already mentioned.