From owner-freebsd-questions@FreeBSD.ORG Thu Nov 8 16:41:12 2007 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 929A216A417 for ; Thu, 8 Nov 2007 16:41:12 +0000 (UTC) (envelope-from bram@diomedia.be) Received: from mail.bvsnv.info (cust142-140.dsl.versadsl.be [62.166.142.140]) by mx1.freebsd.org (Postfix) with ESMTP id 1EA7113C4C8 for ; Thu, 8 Nov 2007 16:41:11 +0000 (UTC) (envelope-from bram@diomedia.be) Received: from [192.168.1.50] ([192.168.1.50]) by mail.bvsnv.info (8.13.6/8.13.6) with ESMTP id lA8Ge9NJ051797; Thu, 8 Nov 2007 17:40:10 +0100 (CET) (envelope-from bram@diomedia.be) Message-ID: <47333C1A.7070709@diomedia.be> Date: Thu, 08 Nov 2007 17:40:58 +0100 From: Bram User-Agent: Thunderbird 1.5.0.12 (X11/20071018) MIME-Version: 1.0 To: Nikos Vassiliadis , freebsd-questions@freebsd.org References: <4731E1A4.6020809@diomedia.be> <200711081408.22387.nvass@teledomenet.gr> In-Reply-To: <200711081408.22387.nvass@teledomenet.gr> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Subject: Re: TCP/IP questions X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 08 Nov 2007 16:41:12 -0000 Nikos Vassiliadis schreef: > On Wednesday 07 November 2007 18:02:44 Bram wrote: > >> Hi all, >> >> Can you change the timeout for a tcp connection ? >> I need to do the following: start a tcp connection , unplug the network >> cable (it's actually wifi but the effect is the same),send some data >> over the connection,wait 20 seconds , reinsert the network cable and >> just keep working. >> When you normally do this the connection will be dead. >> Is there a way in freebsd to change this ? are there parameters wich you >> can set so that the above would work (20 seconds without network can >> happen) ? >> > > TCP using the default FreeBSD settings, can survive > 20 secs of inactivity. It can be an application forced > timeout. What application/protocol are talking about? > > Nikos > This is the more full explanation: I have setup a mobile pc to roam across our building. By reducing the dwell time and changing the channel list to only the channels I use roaming now works within ten seconds en sometimes within one or two seconds. The previous configuration was with fedora and there I was unable to get roaming time under 25 seconds. I do have one very annoying problem however and I have no idea how to solve it. The software uses psycopg (a python postgresql module) wich uses the standard system parameters for connections (At least that is what I think). -On fedora if the connection gets lost and it takes 30 seconds to remake a new connection operation is not interupted, after the 30 seconds you get the data you've been waiting for. -On freebsd however we get it a lot that the connection is "lost", you can easily start a new connection wich works fine, but the old connection you wore using stops working and the app. hangs (If I had to guess I would say that roaming works about 95% of the time and the connection is lost about 5% of the time). I also get a lot of IFDOWN IFUP messages but this seems normal to me. I am now going to program something in twisted using udp to see if this works better. kind regards