When I switch network mode to NAT mode, there's no options regarding Promiscous Mode anymore.
So VirtualBox explicitly doesn't allow it. Why is that?
1 Answer
"Promiscuous mode" means the VM is allowed to receive Ethernet packets sent to different MAC addresses than its own.
In "NAT" mode, each VM is behind a virtual router that performs IP address translation in pretty much the same way home routers/gateways with NAT do – as a side effect it rejects any incoming packets unless they belong to a connection already established by the VM.
This means that the VM will never receive packets sent to other Ethernet addresses because 100% of them would be discarded by the NAT, so the promisc option would be ineffective anyway.
