Hello! man page: cloned_interfaces (str) Set to the list of clonable network interfaces to cre- ate on this host. Further cloning arguments may be passed to the ifconfig(8) create command for each interface by setting the create_args_<interface> variable. If an interface name is specified with ``:sticky'' keyword, the interface will not be destroyed even when rc.d/netif script is invoked with ``stop'' argument. This is useful when reconfiguring the interface without destroying it. Entries in cloned_interfaces are automatically appended to network_interfaces for configuration. Questions not answered: - What it actually does? Repeats packets? Creates some kind of dummy device? - When I (don't) need it? - Security implications? - Performance implications? if_bridge uses it but it's not referenced.
Please post a question to a public mailling list such as freebsd-questions, not to submit it as a problem report.
It's not a mailing list question. Manual or handbook has to give an explanation of the parameter. Otherwise it's a undocumented feature. Common networking such as bridge and epair uses it, which are core components so it has to be explained properly through documentation. Not random people at mailing list.