From owner-freebsd-questions@FreeBSD.ORG  Tue Nov  4 14:42:16 2008
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
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 BD8BC106567A
	for <freebsd-questions@freebsd.org>;
	Tue,  4 Nov 2008 14:42:16 +0000 (UTC)
	(envelope-from keramida@ceid.upatras.gr)
Received: from igloo.linux.gr (igloo.linux.gr [62.1.205.36])
	by mx1.freebsd.org (Postfix) with ESMTP id 062248FC12
	for <freebsd-questions@freebsd.org>;
	Tue,  4 Nov 2008 14:42:15 +0000 (UTC)
	(envelope-from keramida@ceid.upatras.gr)
Received: from kobe.laptop (adsl20-3.kln.forthnet.gr [77.49.147.3])
	(authenticated bits=128)
	by igloo.linux.gr (8.14.3/8.14.3/Debian-5) with ESMTP id mA4Eg30N016066
	(version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT);
	Tue, 4 Nov 2008 16:42:10 +0200
Received: from kobe.laptop (kobe.laptop [127.0.0.1])
	by kobe.laptop (8.14.3/8.14.3) with ESMTP id mA4Eg2xP093574;
	Tue, 4 Nov 2008 16:42:02 +0200 (EET)
	(envelope-from keramida@ceid.upatras.gr)
Received: (from keramida@localhost)
	by kobe.laptop (8.14.3/8.14.3/Submit) id mA4Eg2Nj093573;
	Tue, 4 Nov 2008 16:42:02 +0200 (EET)
	(envelope-from keramida@ceid.upatras.gr)
From: Giorgos Keramidas <keramida@ceid.upatras.gr>
To: "J MPZ" <joompz@gmail.com>
References: <e56958de0811031643s473b499haa3243de1ed7c278@mail.gmail.com>
	<490FA51F.7010901@datapipe.com>
	<e56958de0811040510s494c898fra3ac683392ba2028@mail.gmail.com>
Date: Tue, 04 Nov 2008 16:42:01 +0200
In-Reply-To: <e56958de0811040510s494c898fra3ac683392ba2028@mail.gmail.com>
	(J. MPZ's message of "Tue, 4 Nov 2008 11:10:25 -0200")
Message-ID: <87mygfv9hi.fsf@kobe.laptop>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.0.60 (berkeley-unix)
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
X-MailScanner-ID: mA4Eg30N016066
X-Hellug-MailScanner: Found to be clean
X-Hellug-MailScanner-SpamCheck: not spam, SpamAssassin (not cached,
	score=-3.853, required 5, autolearn=not spam, ALL_TRUSTED -1.80,
	AWL 0.55, BAYES_00 -2.60)
X-Hellug-MailScanner-From: keramida@ceid.upatras.gr
X-Spam-Status: No
Cc: freebsd-questions@freebsd.org
Subject: Re: Problems with FreeBSD
X-BeenThere: freebsd-questions@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: User questions <freebsd-questions.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
	<mailto:freebsd-questions-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-questions>
List-Post: <mailto:freebsd-questions@freebsd.org>
List-Help: <mailto:freebsd-questions-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
	<mailto:freebsd-questions-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 04 Nov 2008 14:42:16 -0000

On Tue, 4 Nov 2008 11:10:25 -0200, "J MPZ" <joompz@gmail.com> wrote:
> Hi Paul,
>
> When my connections freeze, I open the tcpdump in other terminal. If I type
> something, type "Enter", on the terminal frozen, the tcpdump show packets,
> like that:
>
> 11:18:45.526256 IP (tos 0x0, ttl  51, id 651, offset 0, flags [DF], proto:
> TCP (6), length: 112) 189.21.230.195.20787 > 201.57.5.2.2264: P 193:241(48)
> ack 0 win 15136 <nop,nop,timestamp 1556398494 745829191,nop,nop,sack 1
> {1428:1664}>
[...]

> I'm using: tcpdump -nvvv -i ste0 host REMOTE_IP

Can you try capturing the connection setup packets, so we can look at
the TCP MSS negotiation values?  Starting TCPDUMP *before* one of the
connections that stall is made should capture that.

There may be an intermediate router or firewall that blocks ICMP and
ends up breaking path MTU discovery.  I've seen TCP connections
'stall' when path-mtu was broken by a setup like this and one of the
intermediate routers started dropping TCP packets that were too large
for one of its interfaces.