pfSense

tcpdump is failing when zerocopy is enabled (net.bpf.zerocopy_enable=1) which is the default.

Sample failure message:

: tcpdump -i em0
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on em0, link-type EN10MB (Ethernet), capture size 65535 bytes
tcpdump: pcap_loop: BIOCROTZBUF: Capabilities insufficient

I had seen this a few weeks back but only on a vtnet interface. At the time, gnn found the bug in FreeBSD, but the fix does not seem to have made its way into pfSense 2.3 yet.

I've tried with multiple types of NICs (vmx, vtnet, em --real and virtualized, and re) -- same behavior on all. All on current snapshots.