From owner-freebsd-hackers Mon Apr 28 18:26:02 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id SAA13137 for hackers-outgoing; Mon, 28 Apr 1997 18:26:02 -0700 (PDT) Received: from whistle.com (s205m131.whistle.com [207.76.205.131]) by hub.freebsd.org (8.8.5/8.8.5) with ESMTP id SAA13132 for ; Mon, 28 Apr 1997 18:26:00 -0700 (PDT) Received: (from smap@localhost) by whistle.com (8.7.5/8.6.12) id SAA00227; Mon, 28 Apr 1997 18:25:29 -0700 (PDT) Received: from bubba.whistle.com(207.76.205.7) by whistle.com via smap (V1.3) id sma000223; Mon Apr 28 18:25:20 1997 Received: (from archie@localhost) by bubba.whistle.com (8.7.5/8.6.12) id SAA17527; Mon, 28 Apr 1997 18:25:20 -0700 (PDT) From: Archie Cobbs Message-Id: <199704290125.SAA17527@bubba.whistle.com> Subject: Re: Bizzare Ping (and other) bugs. In-Reply-To: <199704251438.KAA23135@seine.cs.umd.edu> from Rohit Dube at "Apr 25, 97 10:38:38 am" To: rohit@cs.umd.edu (Rohit Dube) Date: Mon, 28 Apr 1997 18:25:20 -0700 (PDT) Cc: hackers@freebsd.org X-Mailer: ELM [version 2.4ME+ PL25 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk > I was wondering if anybody had encountered/solved the following ping bug - > > [1] Change the IP address of an interface (using ifconfig). > [2] Ping a target machine from that interface. No response. > [3] Look at the exchange using 'tcpdump'. The ping packets going out > of the 'changed' interface have the old address. ICMP echo replies > from the target machine are to this old address and are not delivered > to ping. Yep, we've seen it :-) > In general FreeBSD/4.4BSD code for changed/downed/deleted interfaces/routes at > run-time seems to be lacking. Easier noted than fixed, unfortunately... but maybe someday... Julian E. has looked at this a good deal. The problem is that the networking code isn't real good at keeping track of what's pointing at what other structures, and it can't completely free old interface addresses since a route in the routing table may still point to it, etc. That's my level of detail of understanding anyway. -Archie ___________________________________________________________________________ Archie Cobbs * Whistle Communications, Inc. * http://www.whistle.com