From owner-freebsd-questions@FreeBSD.ORG Mon Mar 21 17:21:46 2005 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CC01316A4CE for ; Mon, 21 Mar 2005 17:21:46 +0000 (GMT) Received: from smtpout.mac.com (smtpout.mac.com [17.250.248.45]) by mx1.FreeBSD.org (Postfix) with ESMTP id 6524343D1F for ; Mon, 21 Mar 2005 17:21:46 +0000 (GMT) (envelope-from cswiger@mac.com) Received: from mac.com (smtpin08-en2 [10.13.10.153]) by smtpout.mac.com (Xserve/MantshX 2.0) with ESMTP id j2LHLkFo007594; Mon, 21 Mar 2005 09:21:46 -0800 (PST) Received: from [10.1.1.245] (nfw2.codefab.com [199.103.21.225] (may be forged)) (authenticated bits=0)j2LHLiMr020601; Mon, 21 Mar 2005 09:21:45 -0800 (PST) In-Reply-To: <423EFE41.6040805@web.de> References: <423EFE41.6040805@web.de> Mime-Version: 1.0 (Apple Message framework v619.2) Content-Type: text/plain; charset=US-ASCII; format=flowed Message-Id: <56b90b3668acea792519e1e70a7b837a@mac.com> Content-Transfer-Encoding: 7bit From: Charles Swiger Date: Mon, 21 Mar 2005 12:21:41 -0500 To: Robert Gogolok X-Mailer: Apple Mail (2.619.2) cc: freebsd-questions@freebsd.org Subject: Re: FIN_WAIT_2 X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 21 Mar 2005 17:21:47 -0000 On Mar 21, 2005, at 12:02 PM, Robert Gogolok wrote: > The webserver is running FreeBSD, and currently I get many FIN_WAIT_2 > states: > # netstat -n -p tcp | grep FIN_WAIT_2 | wc -l > 48 > > I wonder WHAT is responsible for sending every 5 minutes ACK messages > to the clients in FIN_WAIT_2 state? tcp.inet.tcp.always_keepalive > seems to be something else The TCP stack wants the remote end to acknowledge the last FIN it sends and close the connection cleanly, and there is a timer (2 * MSL?) which gets started when a connection moves into the closing stages (FIN_WAIT_1, FIN_WAIT_2, LAST_ACK). It's not uncommon for some clients (think dialup users running Win98), to drop the connection rather rather than close it properly. Your system should time out these connections after a while. -- -Chuck