[comp.protocols.tcp-ip] 4.3bsd/watching icmp traffic

stanonik@NPRDC.NAVY.MIL (Ron Stanonik) (10/19/90)

We've modified a copy of 4.3bsd ping to just watch icmps
received; ie, not ping, just watch.  We've got it running
on our gateway, a vax running 4.3bsd.  We'd also like to
see icmps being forwarded through the vax.  Any suggestions?
Maybe using some socket type other than SOCK_RAW?  Or maybe
4.3bsd just doesn't give applications a chance to get their
hands on packets being forwarded?

Thanks,

Ron Stanonik
stanonik@nprdc.navy.mil

mankin@GATEWAY.MITRE.ORG (10/24/90)

Ron,

We distribute a program that gets compiled into the 4.3 kernel and
lets applications read any or all IP traffic that is being forwarded.
It is called NETMON/iptrace.  The code and a document explaining
how it works and how to install it can be anonymously ftp'd
from aelred-3.ie.org (192.48.115.36): pub/netmon.tar or pub/netmon.tar.Z.
For your requirement, you would want to compile only the instrumented
ip_input.c.  Otherwise, follow the directions as given.  By the
way, the overhead of NETMON is about 5% or less, depending on the
packet arrival rate.  And iptrace uses CPU on the same order as the
gated executable.  

A. Mankin
mankin@gateway.mitre.org
MITRE-Washington Networking Center