Thanks for validating James. I’m running netmap + netmap-libpcap and then compiled tcpdump 4.9.0. So looking like a netmap bug. > On Mar 18, 2017, at 3:30 PM, James Lay <jlay at slave-tothe-box.net> wrote: > > That's weird....I can't reproduce that here...on Ubuntu 16 across the board here. Maybe libpcap or interface issue? My only guess. >