I have made available sniffer-2_1.dd.gz, a 3.5" HD disk image
for the x86 architecture.

It is located at:

ftp://ftp.unit.no/pub/NetBSD/contrib/sniffer-2_1.dd.gz

The disk is basically a tcpdump diskette, for debugging network problems.
It was created (with a little coaxing) by mkboot 2.1, hence the version.
You will need a kernel (boot) diskette in order to use it.
Program binaries were created on a NetBSD-1.2 (Beta) system.

Thanks to Havard Eidnes for making it available via FTP.