From debbugs-submit-bounces@debbugs.gnu.org Sun May 15 22:50:26 2016 Received: (at submit) by debbugs.gnu.org; 16 May 2016 02:50:26 +0000 Received: from localhost ([127.0.0.1]:53137 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1b28by-0000nK-Dp for submit@debbugs.gnu.org; Sun, 15 May 2016 22:50:26 -0400 Received: from mail-pf0-f180.google.com ([209.85.192.180]:36823) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1b28bv-0000n0-Uc for submit@debbugs.gnu.org; Sun, 15 May 2016 22:50:24 -0400 Received: by mail-pf0-f180.google.com with SMTP id c189so64416169pfb.3 for ; Sun, 15 May 2016 19:50:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:subject:date:message-id:mime-version; bh=7nA3KU1TcWCt72jodYnSjDcsfXXBenYkzuhufGAeD4U=; b=c+7agnH705WITf3xC9/w19aFn2j8Fo0nmUmdGFD4uXD1ep8G9Xly9uCjVEVLUydBYq h83Xhduo1A1iLX+VbQhWN0L9v6cqvudPx0aVKbMoqYlB5kqAJnIdM+R6s+VwonaV0Bz5 lPoB1voCi4EdYpxwmNSeEztdvjJsfogZkztnV38DrTIfKFu5eH3YjsZKTYUBLYZH6TLL rtfi+HUd/oxssHwaKyzFSehGbnfo8wA6Klvmh6x3BgxOou5z9H9b0cHtvTMObBdfBpz3 wB+eg/HM1iHTINW6NXk+YYo6YGUTnOtkSgyft7nVaIAAwr3856uUdV3/OyiNPCvf2idY VJFQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:sender:from:to:subject:date:message-id :mime-version; bh=7nA3KU1TcWCt72jodYnSjDcsfXXBenYkzuhufGAeD4U=; b=jyu/krvIb0DE0iCX1uhh9oy8m484xou5qlgSwCGCAx5Uz1/s3IWGho/iCu3PtYXVYz wgKAwaM673YAMOku5xMSkqGawpL9x1MV2N/D0jLNFrQJxC6b3xrEba3WYPBnqedSKE8q CSpGLvkVoXPigzXa0qt5801h3te/58CrNk241tQhRpX+mXsG7VnARQVsFQhl2MZKBYq7 MaeSo19OLyBgC3xQzo0AB96Z680QPJSuFr92ZwRIZbE4x9ce2+iEwOfA57ypB+yJLvfN PnhSEOAEe/XXxTBXM1RE8dJk9m53EC3pvycposKtIagTW/iaYg0cnZ4TO+oQmkBb3pr/ EJeg== X-Gm-Message-State: AOPr4FXUrrXAsBD8f98ifahE2k84borl7XXFiG32q2jxWf2fMieg+C7YsKsqbFj3t25QeA== X-Received: by 10.98.49.133 with SMTP id x127mr41359362pfx.36.1463367017987; Sun, 15 May 2016 19:50:17 -0700 (PDT) Received: from tsparkle ([155.69.18.175]) by smtp.gmail.com with ESMTPSA id uw2sm43261081pac.10.2016.05.15.19.50.16 for (version=TLSv1/SSLv3 cipher=OTHER); Sun, 15 May 2016 19:50:17 -0700 (PDT) From: Chong Yidong To: submit@debbugs.gnu.org Subject: debbugs.gnu.org MTU / icmp black hole issue Date: Mon, 16 May 2016 10:47:51 +0800 Message-ID: <87h9dyiuqw.fsf@gmail.com> MIME-Version: 1.0 Content-Type: text/plain X-Spam-Score: -0.5 (/) X-Debbugs-Envelope-To: submit X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -0.5 (/) Package: debbugs.gnu.org Just received the following bug report, which I'm forwarding here. ---------- Forwarded message ---------- From: Janne Snabb Date: Sun, May 15, 2016 at 5:28 PM Subject: debbugs.gnu.org MTU / icmp black hole issue Hi, I was wondering why my email to debbugs.gnu.org was stuck. After researching with tcpdump and ping it appears that this server is using or is behind a network which uses MTU which is smaller than normal but it is not advertising that correctly in TCP MSS and not informing the client about blackholed backets with icmp. The advertised TCP MSS value is too high. Packets that big end up in a black hole and the email delivery TCP connection stalls. There may be some icmp blackholing involved as well. Just FYI. It would be a good idea to fix this. The current setup is very broken. I was able to work around this issue and get my email (including this one) delivered by using sysctl -w net.ipv4.tcp_mtu_probing=1 on client side. -- Janne Snabb snabb@epipe.com From debbugs-submit-bounces@debbugs.gnu.org Mon May 16 03:22:26 2016 Received: (at control) by debbugs.gnu.org; 16 May 2016 07:22:26 +0000 Received: from localhost ([127.0.0.1]:53201 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1b2CrC-0007As-IE for submit@debbugs.gnu.org; Mon, 16 May 2016 03:22:26 -0400 Received: from eggs.gnu.org ([208.118.235.92]:50715) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1b2CrB-0007Ag-7K for control@debbugs.gnu.org; Mon, 16 May 2016 03:22:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b2Cr5-0000l9-CE for control@debbugs.gnu.org; Mon, 16 May 2016 03:22:20 -0400 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on eggs.gnu.org X-Spam-Level: X-Spam-Status: No, score=-3.3 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD autolearn=disabled version=3.3.2 Received: from fencepost.gnu.org ([2001:4830:134:3::e]:54076) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b2Cr5-0000kl-9y for control@debbugs.gnu.org; Mon, 16 May 2016 03:22:19 -0400 Received: from rgm by fencepost.gnu.org with local (Exim 4.82) (envelope-from ) id 1b2Cr3-0005pr-Ll for control@debbugs.gnu.org; Mon, 16 May 2016 03:22:17 -0400 Subject: control message for bug 23547 To: X-Mailer: mail (GNU Mailutils 2.99.98) Message-Id: From: Glenn Morris Date: Mon, 16 May 2016 03:22:17 -0400 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2001:4830:134:3::e X-Spam-Score: -6.4 (------) X-Debbugs-Envelope-To: control X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -6.4 (------) submitter 23547 snabb@epipe.com From debbugs-submit-bounces@debbugs.gnu.org Mon May 16 03:25:37 2016 Received: (at 23547) by debbugs.gnu.org; 16 May 2016 07:25:37 +0000 Received: from localhost ([127.0.0.1]:53211 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1b2CuH-0007GE-0i for submit@debbugs.gnu.org; Mon, 16 May 2016 03:25:37 -0400 Received: from eggs.gnu.org ([208.118.235.92]:54074) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1b2CuF-0007Fx-T2 for 23547@debbugs.gnu.org; Mon, 16 May 2016 03:25:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b2Ctq-0002G8-MN for 23547@debbugs.gnu.org; Mon, 16 May 2016 03:25:30 -0400 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on eggs.gnu.org X-Spam-Level: X-Spam-Status: No, score=-0.6 required=5.0 tests=BAYES_50,RP_MATCHES_RCVD autolearn=disabled version=3.3.2 Received: from fencepost.gnu.org ([2001:4830:134:3::e]:54141) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b2CtM-0001sZ-CD; Mon, 16 May 2016 03:24:40 -0400 Received: from rgm by fencepost.gnu.org with local (Exim 4.82) (envelope-from ) id 1b2CtL-0006LW-Ga; Mon, 16 May 2016 03:24:39 -0400 From: Glenn Morris To: snabb@epipe.com Subject: Re: bug#23547: debbugs.gnu.org MTU / icmp black hole issue References: <87h9dyiuqw.fsf@gmail.com> X-Spook: number key Telex Decapitated Pipe bomb Firefly BROMURE X-Ran: :r]1lC19|R(T9tY0u~qG2-h/PH5vT=7*nOOuPa.p#odxU\nj$T!7.{z|,7| X-Hue: black X-Attribution: GM Date: Mon, 16 May 2016 03:24:39 -0400 In-Reply-To: <87h9dyiuqw.fsf@gmail.com> (Chong Yidong's message of "Mon, 16 May 2016 10:47:51 +0800") Message-ID: <6cvb2exy6g.fsf@fencepost.gnu.org> User-Agent: Gnus (www.gnus.org), GNU Emacs (www.gnu.org/software/emacs/) MIME-Version: 1.0 Content-Type: text/plain X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2001:4830:134:3::e X-Spam-Score: -6.4 (------) X-Debbugs-Envelope-To: 23547 Cc: 23547@debbugs.gnu.org X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -6.4 (------) > After researching with tcpdump and ping it appears that this server is > using or is behind a network which uses MTU which is smaller than normal > but it is not advertising that correctly in TCP MSS and not informing > the client about blackholed backets with icmp. The advertised TCP MSS > value is too high. Packets that big end up in a black hole and the email > delivery TCP connection stalls. There may be some icmp blackholing > involved as well. Thanks for the report. Sadly, I only understand about one word in three, so I have no idea what to do to fix this. :( Can anyone help? From debbugs-submit-bounces@debbugs.gnu.org Mon May 16 14:33:38 2016 Received: (at 23547) by debbugs.gnu.org; 16 May 2016 18:33:38 +0000 Received: from localhost ([127.0.0.1]:54268 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1b2NKk-0003mp-LY for submit@debbugs.gnu.org; Mon, 16 May 2016 14:33:38 -0400 Received: from mail.fsf.org ([208.118.235.13]:32940) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1b2NHa-0003hP-8K for 23547@debbugs.gnu.org; Mon, 16 May 2016 14:30:22 -0400 Received: from jumpgate.fsf.org ([74.94.156.211]:32887 helo=rms) by mail.fsf.org with esmtps (TLS-1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.69) (envelope-from ) id 1b2NHZ-00027v-Pj for 23547@debbugs.gnu.org; Mon, 16 May 2016 14:30:22 -0400 Date: Mon, 16 May 2016 14:30:18 -0400 From: Lisa Marie Maginnis To: 23547@debbugs.gnu.org Subject: Re: bug#23547: debbugs.gnu.org MTU / icmp black hole issue Message-ID: <20160516183018.GC5042@rms> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) X-detected-operating-system: by mail.fsf.org: GNU/Linux 2.2.x-3.x [generic] X-Spam-Score: -6.4 (------) X-Debbugs-Envelope-To: 23547 X-Mailman-Approved-At: Mon, 16 May 2016 14:33:37 -0400 X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -6.4 (------) > After researching with tcpdump and ping it appears that this server is > using or is behind a network which uses MTU which is smaller than normal > but it is not advertising that correctly in TCP MSS and not informing > the client about blackholed backets with icmp. The advertised TCP MSS > value is too high. Packets that big end up in a black hole and the email > delivery TCP connection stalls. There may be some icmp blackholing > involved as well. Hello, Thanks for your report. We have resolved this issue on our end by lowering the TCP MSS value advertised on connections coming out of the network in question. We are currently using an MSS of 1394 to accomedate links with an MTU less than 1500. If you are still seeing this issue, let us know! Thanks & Happy Hackingz, -- ~Lisa Marie Maginnis Senior System Administrator Free Software Foundation http://fsf.org http://gnu.org GPG Key: 61EEC710 From debbugs-submit-bounces@debbugs.gnu.org Mon May 16 14:36:40 2016 Received: (at control) by debbugs.gnu.org; 16 May 2016 18:36:40 +0000 Received: from localhost ([127.0.0.1]:54272 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1b2NNg-0003rO-4q for submit@debbugs.gnu.org; Mon, 16 May 2016 14:36:40 -0400 Received: from havoc.proulx.com ([96.88.95.61]:45937) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1b2NNe-0003r9-AF for control@debbugs.gnu.org; Mon, 16 May 2016 14:36:38 -0400 Received: from joseki.proulx.com (localhost [127.0.0.1]) by havoc.proulx.com (Postfix) with ESMTP id 5E1555FA for ; Mon, 16 May 2016 12:36:31 -0600 (MDT) Received: from hysteria.proulx.com (hysteria.proulx.com [192.168.230.119]) by joseki.proulx.com (Postfix) with ESMTP id 097EF217F7 for ; Mon, 16 May 2016 12:36:31 -0600 (MDT) Received: by hysteria.proulx.com (Postfix, from userid 1000) id D8EE32DC49; Mon, 16 May 2016 12:36:30 -0600 (MDT) Date: Mon, 16 May 2016 12:36:30 -0600 From: Bob Proulx To: control@debbugs.gnu.org Subject: close ticket Message-ID: <20160516123514680591070@bob.proulx.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.24 (2015-08-30) X-Spam-Score: -1.4 (-) X-Debbugs-Envelope-To: control X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -1.4 (-) close 23547 stop Since this has been responded to and the issue should now be resolved I will close the ticket. Please continue the discussion if it is not. From debbugs-submit-bounces@debbugs.gnu.org Mon May 16 14:51:49 2016 Received: (at 23547) by debbugs.gnu.org; 16 May 2016 18:51:49 +0000 Received: from localhost ([127.0.0.1]:54317 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1b2NcK-0005wV-OJ for submit@debbugs.gnu.org; Mon, 16 May 2016 14:51:48 -0400 Received: from eggs.gnu.org ([208.118.235.92]:44613) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1b2NcJ-0005wI-N2 for 23547@debbugs.gnu.org; Mon, 16 May 2016 14:51:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b2NcD-0003lY-QY for 23547@debbugs.gnu.org; Mon, 16 May 2016 14:51:42 -0400 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on eggs.gnu.org X-Spam-Level: X-Spam-Status: No, score=-3.3 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD autolearn=disabled version=3.3.2 Received: from fencepost.gnu.org ([2001:4830:134:3::e]:36100) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b2NcD-0003lT-Nl for 23547@debbugs.gnu.org; Mon, 16 May 2016 14:51:41 -0400 Received: from rgm by fencepost.gnu.org with local (Exim 4.82) (envelope-from ) id 1b2NcD-0004tX-4C; Mon, 16 May 2016 14:51:41 -0400 From: Glenn Morris To: 23547@debbugs.gnu.org Subject: Re: bug#23547: debbugs.gnu.org MTU / icmp black hole issue References: <87h9dyiuqw.fsf@gmail.com> <6cvb2exy6g.fsf@fencepost.gnu.org> X-Spook: Biological infection Blowfish MD2 Incident Mahmoud X-Ran: K'N$C5Z{MbjTP1sP5@_M1C0,SlQ7!c]}s6wo/Eln)Y!YKT2L<+@qGfQCeJr*69yx:|:]S[ X-Hue: red X-Attribution: GM Date: Mon, 16 May 2016 14:51:40 -0400 In-Reply-To: <6cvb2exy6g.fsf@fencepost.gnu.org> (Glenn Morris's message of "Mon, 16 May 2016 03:24:39 -0400") Message-ID: User-Agent: Gnus (www.gnus.org), GNU Emacs (www.gnu.org/software/emacs/) MIME-Version: 1.0 Content-Type: text/plain X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2001:4830:134:3::e X-Spam-Score: -6.4 (------) X-Debbugs-Envelope-To: 23547 X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -6.4 (------) For the record, this was manifesting in the exim logs as "SMTP data timeout (message abandoned)" From unknown Sun Jun 22 08:04:10 2025 Received: (at fakecontrol) by fakecontrolmessage; To: internal_control@debbugs.gnu.org From: Debbugs Internal Request Subject: Internal Control Message-Id: bug archived. Date: Tue, 14 Jun 2016 11:24:04 +0000 User-Agent: Fakemail v42.6.9 # This is a fake control message. # # The action: # bug archived. thanks # This fakemail brought to you by your local debbugs # administrator