Rubén González Arnau wrote:
[ ... ]
> When I use tcpdump, I see this error
> 
> sw2:~# tcpdump -i pflog0
> tcpdump: WARNING: pflog0: no IPv4 address assigned
> tcpdump: libpcap: unknown data link type 0x75
> 
> My NetBSD version is 2.0.2, any idea?

Data link type 0x75 corresponds to this (from <net/bpf.h> on a FreeBSD system):

/*
  * Reserved for use in capture-file headers as a link-layer type
  * corresponding to OpenBSD DLT_PFLOG; DLT_PFLOG is 17 in OpenBSD,
  * but that's DLT_LANE8023 in SuSE 6.3, so we can't use 17 for it
  * in capture-file headers.
  */
#define DLT_PFLOG       117

I would guess that NetBSD has not completely imported this pflog functionality, 
yet.  You should be able to tcpdump against a normal interface, however.

-- 
-Chuck