From owner-freebsd-questions Thu Aug 6 13:04:33 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id NAA15900 for freebsd-questions-outgoing; Thu, 6 Aug 1998 13:04:33 -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 NAA15804 for ; Thu, 6 Aug 1998 13:04:16 -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 PAA00300 for ; Thu, 6 Aug 1998 15:03:44 -0500 (CDT) (envelope-from sysadmin@mfn.org) Received: by noc.mfn.org with Microsoft Mail id <01BDC14B.144DE880@noc.mfn.org>; Thu, 6 Aug 1998 15:01:24 -0500 Message-ID: <01BDC14B.144DE880@noc.mfn.org> From: "sysadmin@mfn.org" To: "'freebsd-questions@freebsd.org'" Subject: FTP Symptom of Network Problem... Date: Thu, 6 Aug 1998 15:01:07 -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 Greetings... Before I go any further, here's the map: ________ _____________ _________ (coax) | | (coax) | | (coax) | segment | -------| bridge |----------| 12 Stn. Hub |----------| monitor | | | | (10 Base T) | | wkstn | -------- ------------- --------- "Gate" |... | ... | "monitor" | | | -----------------| | |----------------- | | | | | | ____________ ____________ ____________ | | | NIS/NFS | | | | wkstn "A" | | server | | wkstn "L" | ------------ ------------ ------------ "nodeA" "server" "nodeL" Ok. With that out of the way... This all started because I was getting calls from angry users on machines in this segment, all complaining (*loudly*) about "lag that often runs over 30 seconds". Since these were *users* talking, I figured I had an actual lag of maybe 30 microseconds, but did the right thing, and checked it out anyway. (1) All logs (netstat -i) show no problems: low total utilization (averages about 5 million packets a day), with the occassional Ierr (often zero, some as high as 10). Except for where I specifically note otherwise, the collision rates run about 1.5%. All machines have an average cpu utilization of close to zero, with the peak being on "server" of about 60%. Except for "server", all machines are 486 hardware, with from 16mb to 128mb of ram. "Server" is a P200 with 128mb of ram. There is no "X" in use anywhere (not even loaded - I double checked). (2) after investigating the complaints, the "lag" is *only* reported when using telnet or ftp, although I am unable to verify it from personal experience (and I have *really* tried! - Just like going to the doctor, as soon as you look for it, it's gone!). At least on any "user" machine ("A" through "L") - see next paragraph. (3) In an attempt to get a better look at things, I took a machine from another segment, and put it on here. The plan was for this machine to be a full-time monitor (as the name above shows). Using "monitor", I was finally able to experience problems myself, although only in FTP. When logged in to "monitor", FTP speeds in retrieving files from "server" runs under 10kbps, when it runs at all. Often it will time out and be "reset by peer". It's not that bad packets are being sent and resent: there is a packet sent, and then a *long* pause, and then another, and the cycle repeats. (4) I can log in to any workstation and ftp from "monitor" at full speed (~750kbps). I can log in to "monitor" and ftp from any workstation at full speed. As far as I can tell (user complaints aside), I can login to any workstation ("A" - "L") and get files full speed from "server", and vice-versa. But as long as I am logged in to "monitor" and trying to get files from "server", I'm in deep trouble. The *only* thing I see "odd" here is a collision rate of about 10% on "monitor". (5) In trying to isolate "monitor"'s problem, I have: > Replaced cabling for both "monitor" and "server" > Replaced NIC's for both "monitor" and "server" > Reloaded the OS for both "M" and "S" > Both raised and lowered "MAXUSERS" for "server" > Placed another machine in "monitor's" position (no effect) 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? J.A. Terranson sysadmin@mfn.org (Please send answers direct, as I am no longer subscribed, thanks!) , and as far as I can *prove*, only in 1 very certain configuration: going from "server" to " To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message