From owner-freebsd-current@FreeBSD.ORG Thu Jul 14 19:14:53 2005 Return-Path: X-Original-To: freebsd-current@freebsd.org Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A4E5B16A41C; Thu, 14 Jul 2005 19:14:53 +0000 (GMT) (envelope-from bakul@bitblocks.com) Received: from gate.bitblocks.com (bitblocks.com [209.204.185.216]) by mx1.FreeBSD.org (Postfix) with ESMTP id 4F0B643D46; Thu, 14 Jul 2005 19:14:53 +0000 (GMT) (envelope-from bakul@bitblocks.com) Received: from bitblocks.com (localhost [127.0.0.1]) by gate.bitblocks.com (8.13.3/8.13.1) with ESMTP id j6EJEneq070016; Thu, 14 Jul 2005 12:14:49 -0700 (PDT) (envelope-from bakul@bitblocks.com) Message-Id: <200507141914.j6EJEneq070016@gate.bitblocks.com> To: Robert Watson In-reply-to: Your message of "Thu, 14 Jul 2005 19:27:10 BST." <20050714192403.H35071@fledge.watson.org> Date: Thu, 14 Jul 2005 12:14:49 -0700 From: Bakul Shah Cc: freebsd-current@freebsd.org Subject: Re: Problems with OpenBSD dhclient X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 14 Jul 2005 19:14:53 -0000 > > More serious is that I can't roam. When I move between APs, dhclient > > exits and I need to manually re-start it. I lose my SSH sessions. Ugh! > > > > Worse, I occasionally see my association drop momentarily when I am > > simply sitting and typing. Once again, dhclient dies and I must manually > > restart it and then re-establish my SSH and recover anything broken when > > the connection dropped. This is fairly serious! I don't understand what > > causes this, but it is infrequent which makes it hard to catch. > > > > It looks like killing dhclient when the interface drops is not a good > > idea. At very least, it needs to give a little time for re-association > > before dropping the DHCP client. > > I'm experiencing similar or identical problems. When at the British > Library the day before yesterday, slight blips in my association would > result in loss of my IP address, requiring manual restarting of dhclient. > > My normal approach for wireless/etc is to settle on a link -- be it wired > ethernet or 802.11, and run dhclient on it to get things going. When > done, I'll typically kill off dhclient. This worked pretty well with the > old dhclient setup, but not so well with the new one. Because I range > over a variety of network environments, from adhoc 802.11, wired ethernet, > to base station based 802.11, I tend to want to say "do this for now", and > have it stick until I move on. Maybe what I need to change is software > configuration -- i.e., devd to re-launch dhclient. But obviously what I'm > doing now isn't working, and results in a pretty poor user experience > (blips or roaming and suddenly the network is gone). To avoid interface flapping perhaps some hysteresis needs to be introduced in dhclient? If a link up event occurs within N seconds of a link down event, ignore them both! N may need to be tunable. Such hysteresis is _not_ needed for administrative up/down -- when I say `ifconfig ath0 down', I want it down *now*! Devd does need to relaunch dhclient (& wpa_supplicant etc.) on a genuine link up event.