I have 3 computers on the same sub-net. Computer A and B are communicating with each other (ping, telnet, etc.). I'd like to see the packets between A and B on computer C. Is it possible to do this with tcpdump? I've read the manual and Googled this to no end but I can't make it work. tcpdump running on C does not see traffic between A and B. I know tcpdump is working because if either A or B pings C, tcpdump shows the network traffic. I've also manually put the interface on promiscuous mode (ifconfig ethx promisc) but still no output.
Comp-A, IP: 192.168.0.100
ping Comp-B ==> Comp-A gets reply from Comp-B
Comp-B, IP: 192.168.0.101
tcpdump -Xi eth1 ==> Sees ping packets from Comp-A
Comp-C, IP: 192.168.0.102
tcpdump -Xi eth1 ==> No output, just the generic tcpdump initial message