Why are virtual machines not pinged?

Question

linux

Hello.
My main linux machine is:
wlp0s20f3: 192.168.1.9
I created 3 virtual machines in VirtulBox. Each one configured like this:


10:192.168.1.4
10.1:192.168.1.5
kali:192.168.1.20
PC:192.168.1.9

The problem is that:
4 pings 9.20 but doesn't ping 5
5 pings 9.20 but doesn't pings 4
20 pings 9 but does not ping 4.5
9 pings 20 but does not ping 4.5

everyone knows about arp tables. What could be the problem ?

Answer 1

probably in the firewall

Answer 2

They have NAT