When list virtual network interfaces, some of them are not anymore needed:
vboxnet1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 0a:00:27:00:00:01
vboxnet8: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 0a:00:27:00:00:08
vboxnet9: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 0a:00:27:00:00:09
vboxnet11: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 0a:00:27:00:00:0b
vboxnet12: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 0a:00:27:00:00:0c
How can I make them disable them for good?
It turns out VirtualBox comes natively with a special command dedicated to this need:
e.g. to remove the network interface vboxnet0, execute the following command
VBoxManage hostonlyif remove vboxnet0