A copy of this package can be found at: 
WWW: http://security.uchicago.edu/tools/net-forensics/

This package is a port of TAMU's extract program from NetLogger to look
at flow data instead of netlogger data. Blame Larry for it's faults, not
TAMU. Blame me for the FreeBSD port, not Larry :-)

If you don't already have a good guess what this program does and what
data it is looking for, the odds are that it isn't going to be of much
help to you. This program only works on Cisco flow data as captured
with Mark Fullmer's flowtools package. If you don't have that, get that
first, then look at this program.

In order for this to compile you will need flowtools from Mark
Fullmer's (net-mgmt/flow-tools port).