How to isolate the network and only allow internet?

Question

virtual box

Hello. I'm setting up Cuckoo for tests and ran into an isolation issue.
Given: Physical
machine
Pfsense 2.4.4-RELEASE-p2 (amd64) Interfaces - igb0 (WAN) igb1 (LAN1 10.10.10.0/24) BR0 (LAN2 10.10.20.0/24 bridge of 4 mlnx)
Esxi 6.7.0 (Build 8169922 ) vSwitch interfaces (BR0)
Ubuntu 16.04 is raised on Esxi, ens160 interfaces (10.10.20.201) vboxnet0 (192.168.56.1 HOST-ONLY)
Ubuntu is raised VBOX, on which the VM is raised for the test (WIN7 192.168.56.106) The
question is, how to isolate 10.10.20.0/24 and 192.168.56.0/24 between each other and leave only interaction between Ubuntu and VM on VBOX'e + internet?
Current rules in iptables:

[email protected]:/home/cuckoo# iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination

Chain FORWARD (policy DROP)
target     prot opt source               destination

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

Thanks in advance.

Answer 1

to admit the meaning of the question is not clear. for example: "how to isolate 10.10.20.0/24 and 192.168.56.0/24 between themselves" - they are already isolated if you did not configure routing between them. It is not at all clear why a virtual machine should be made in a virtual machine. Not only did you overdo it with virtualization, which has an extremely negative effect on performance, you also confused yourself in networks and their routing. You didn't specify anything about the network Esxi is connected to. Ultimately, it is not entirely clear what exactly you need. If you need to pass traffic from a virtual machine running in a virtual machine, then you need to specify the gateway to the Internet for it, and on the virtual machine in which the virtual machine is running, which needs Internet, you need to configure the forwarding of all traffic from the virtual machine to an external router.