I have a stange behavior when listening traffic on a NO CARRIER interface.(i know it's stupid, but i'm doing tests ...)
I try to reach a connected host and I listen on interface output with tcpdump and some traffic seem so be dumped of an "unknown ethertype". I have a very bad ethenet link connected to this interface, that makes it in NO CARRIER state. When all is right, packet dumped are ARP one. So i have many question about the bahaviour in order to validate my test. Did it possible to send traffic on a no carrier interface (that did not detect link activity) ? Did the dumped traffic is really sent or is it just traffic that "seem" to be sent (software garbage not physical send)? Did that mean that some ethernet traffic can go out of my (no carrier) ethernet card ?
I'm douin my tests with a pcn device and a PC runnning FreeBSD 5.3.
Thx for your answers