From owner-freebsd-hackers  Thu Sep 11 18:50:33 1997
Return-Path: <owner-freebsd-hackers>
Received: (from root@localhost)
          by hub.freebsd.org (8.8.7/8.8.7) id SAA18584
          for hackers-outgoing; Thu, 11 Sep 1997 18:50:33 -0700 (PDT)
Received: from alpo.whistle.com (alpo.whistle.com [207.76.204.38])
          by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id SAA18575
          for <FreeBSD-Hackers@FreeBSD.ORG>; Thu, 11 Sep 1997 18:50:28 -0700 (PDT)
Received: (from daemon@localhost)
	by alpo.whistle.com (8.8.5/8.8.5) id SAA12036;
	Thu, 11 Sep 1997 18:47:44 -0700 (PDT)
Received: from current1.whistle.com(207.76.205.22)
 via SMTP by alpo.whistle.com, id smtpd012034; Fri Sep 12 01:47:42 1997
Message-ID: <34189F1C.FF6D5DF@whistle.com>
Date: Thu, 11 Sep 1997 18:47:08 -0700
From: Julian Elischer <julian@whistle.com>
Organization: Whistle Communications
X-Mailer: Mozilla 3.0Gold (X11; I; FreeBSD 2.2-CURRENT i386)
MIME-Version: 1.0
To: Chuck Robey <chuckr@glue.umd.edu>
CC: FreeBSD-Hackers <FreeBSD-Hackers@FreeBSD.ORG>
Subject: Re: network programming.
References: <Pine.BSF.3.96.970911190130.2260C-100000@Journey2.mat.net>
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Sender: owner-freebsd-hackers@FreeBSD.ORG
X-Loop: FreeBSD.org
Precedence: bulk

Chuck Robey wrote:

man bpf
man tcpdump

> 
> I have to do my very first network programming, a UDP client+server, and I
> was wondering if anyone knows of how I could go about intercepting
> something sent to a UDP socket, so I could use it for troubleshooting?  I
> don't want to receive it (else the client would never get it), just to
> monitor what's going on.  This is my home machine, and I (obviously) have
> root here.
> 
> I don't want the application written for me, just a tool I could use to
> capture what's going on between my buggy server and my buggy client.
> 
> Thanks for any hints, guys.
> 
> ----------------------------+-----------------------------------------------
> Chuck Robey                 | Interests include any kind of voice or data
> chuckr@eng.umd.edu          | communications topic, C programming, and Unix.
> 213 Lakeside Drive Apt T-1  |
> Greenbelt, MD 20770         | I run Journey2 and picnic, both FreeBSD
> (301) 220-2114              | version 3.0 current -- and great FUN!
> ----------------------------+-----------------------------------------------