Trying to get tcpdump to work

[Allen Cole, UUCC]

I am trying to get tcpdump to work.  I have a ds3100 with Ultrix 4.1.  Here
is what I did.

Got tcpdump from gatekeeper.dec.com

made pfilt device (cd /dev; MAKEDEV pfilt)

did pfconfig (/usr/etc/pfconfig +promisc)

made and installed tcpdump (the makefile is already ultrix'ized)

When I run tcpdump as root it says:

# tcpdump host 128.110.48.3
ln0: No such device
tcpdump: your system may not be properly configured; see "man packetfilter(4)"

Also, if I do

/usr/etc/pfconfig + promisc ln0 

it reports no device ln0.

Here is ifconfig ln0

ln0: 128.110.48.6 netmask ffffff00 flags=0x463<DYNPROTO,RUNNING,NOTRAILERS,
BROADCAST,UP>

Anybody see my mistake?  Thanks.

Allen Cole                 University of Utah Computer Center
cole at cc.utah.edu           3440 Merrill Engineering Building
cole at utahcca.bitnet        Salt Lake City, UT 84112
utah-cs!cole               (801) 581-8805