I found the reason by myself. Libpcap uses SIOCGIFINDEX ioctl and according to linux_kernel/net/core/dev_ioctl.c, COLON(':') in interface name is not supposed to be in a name for macvlan. Anything after colon is ignored. Capturing for eth1:2 is same as capturing eth1. Use eth1_2 instead of eth1:2 then problem solved. I wonder there is any document about this. _______________________________________________ tcpdump-workers mailing list tcpdump-workers@lists.tcpdump.org https://lists.sandelman.ca/mailman/listinfo/tcpdump-workers