Core3 no longer reuse netvm own IP for primary DNS. At the same time,
disable dropping traffic to netvm itself because it breaks DNS (as one
of blocked things). This allows VM to learn real netvm IP, but:
- this mechanism is not intended to avoid detection from already
compromised VM, only about unintentional leaks
- this can be prevented using vif-qubes-nat.sh on the netvm itself (so
it will also have hidden its own IP)
QubesOS/qubes-issues#1143
c8213ea55a