From owner-freebsd-questions Wed Aug 12 09:28:54 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id JAA21697 for freebsd-questions-outgoing; Wed, 12 Aug 1998 09:28:54 -0700 (PDT) (envelope-from owner-freebsd-questions@FreeBSD.ORG) Received: from greeves.mfn.org (greeves.mfn.org [204.238.179.3]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id JAA21692 for ; Wed, 12 Aug 1998 09:28:49 -0700 (PDT) (envelope-from sysadmin@mfn.org) Received: from noc.mfn.org (noc.mfn.org [204.238.179.35]) by greeves.mfn.org (8.8.7/8.8.7) with SMTP id LAA02534; Wed, 12 Aug 1998 11:28:15 -0500 (CDT) (envelope-from sysadmin@mfn.org) Received: by noc.mfn.org with Microsoft Mail id <01BDC5E3.91EB31C0@noc.mfn.org>; Wed, 12 Aug 1998 11:23:03 -0500 Message-ID: <01BDC5E3.91EB31C0@noc.mfn.org> From: "sysadmin@mfn.org" To: "'dg@root.com'" , "'dhw@whistle.com'" , "'dwhite@resnet.uoregon.edu'" Cc: "'freebsd-questions@freebsd.org'" Subject: RE: FTP Symptom of Network Problem... Date: Wed, 12 Aug 1998 11:22:41 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG OK, thought the final resolution would be of interest to everyone here, so... (1) The terminator on the "monitor" side of the coax was bad. (2) One of the boxes on the hub *did* have tcp extensions enabled, although this did not seem to affect anything. (3) Having replaced the terminator, the problem did *not* resolve, it merely got "better". I was finally able to experience the phenomenon myself, and track it down to the de0 driver ("server" is de0 based, all the rest are NE2000's). When the de0 driver gets a lot of crc/framing errors, it "gets lost", literally. In order to recover it, you have to (a) wait for it, which could take from 2 seconds to 2 hours, or, (b) reset it by bringing it down/up with ifconfig. I replaced the card with other known good cards, and the problem did not change. The problem with de0 is specific to this subnet however, so I did a little sniffing and research overnight to verify the actual cause/effects here. This error will only occur when the de0 is operating in an environment with a lot of *slow* cards using even slower cpus. When the "bad" de0 card is put in a fairly up-to-date environment (being 486/100 and higher on the same subnet) it performs fine (except for the normally complained about recieve error messages you see on -questions so often). I believe that the de0 driver needs serious looking at (and I am *not* qualified to do it, or I would volunteer). I have only managed to resolve this by scheduling a cron to check connectivity every minute, and do ifconfig down/up if it is found to be wanting: not a really good solution. Please let me know if you need more info on this. Yours, J.A. Terranson sysadmin@mfn.org -----Original Message----- From: David Greenman [SMTP:dg@root.com] Sent: Thursday, August 06, 1998 5:34 PM To: sysadmin@mfn.org Cc: 'freebsd-questions@freebsd.org' Subject: Re: FTP Symptom of Network Problem... >I am completely out of ideas here. I am also completely >out of patience :( I have a dozen angry users that I >can't placate because I can't even verify their problem >(other than on "monitor"), and I have what looks like a >physically impossible interaction between "monitor" and >"server"... > >Anyone have *any* (no matter _how_ off the wall) ideas? A couple of things to try: 1) Make sure that server's ethernet is set to the proper duplex. 2) Check netstat -s on server and look at TCP checksum and other errors. Do the same on a client machine. Also look at retransmits on both sides; you should be able to tell in which direction the problem is occuring by doing this. 3) I didn't see a mention of the type of NIC you were using; whatever that is, you might try something entirely different in the server and a client machine to see if that affects the problem. 4) Move server to a different hub port. -DG David Greenman Co-founder/Principal Architect, The FreeBSD Project To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message