It's great that BPF can be used to implement all kinds of monitoring tools for Linux. But I would really like it if pcap-filter finished implementing basic BPF primitives for IPv6 that have worked in IPv4 since the beginning.

From the pcap-filter(7) manpage: "Note that tcp, udp and other upper-layer protocol types only apply to IPv4, not IPv6 (this will be fixed in the future). "

Sometimes reading posts about BPF makes me think I'm the only one still using it to filter packets.