From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756993Ab1KPQz5 (ORCPT ); Wed, 16 Nov 2011 11:55:57 -0500 Received: from mx3.utsp.utwente.nl ([130.89.2.14]:4802 "EHLO mx.utwente.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756830Ab1KPQzy (ORCPT ); Wed, 16 Nov 2011 11:55:54 -0500 X-Greylist: delayed 2443 seconds by postgrey-1.27 at vger.kernel.org; Wed, 16 Nov 2011 11:55:54 EST Subject: Routing problem on PTPP server since kernel 2.6.39 From: Jeroen van Ingen To: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Date: Wed, 16 Nov 2011 17:14:59 +0100 Message-ID: <1321460099.3366.49.camel@icts-sp-039> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 Content-Transfer-Encoding: 7bit X-UTwente-MailScanner-Information: Scanned by MailScanner. Contact icts.servicedesk@utwente.nl for more information. X-UTwente-MailScanner: Found to be clean X-UTwente-MailScanner-From: jeroen@zijndomein.nl Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, We're in the process of upgrading our Linux-based (Ubuntu) VPN servers and running into a problem with PPTP connections. So far, we have been able to narrow it down to the following: Problem: * First PPTP client connects successfully, consecutive PPTP clients can't connect. Cause seems to be: RADIUS authentication times out because DHCP address allocation fails, because somehow the DHCPDISCOVER to 255.255.255.255 is routed out ppp0 and not out of eth0. * Routing tables look fine, both before and after first PPTP client is connected. * Route cache however shows an entry for 255.255.255.255. pointing towards ppp0 and we can't explain how it got there. After flushing the route cache this entry quickly reappears. Last kernel working OK: * 2.6.38 Kernels where we hit this issue: * First: 2.6.39 * Most recent one tested: 3.1.1 * All tested kernels are from Ubuntu repository. Questions: * Is this the correct list to assist in troubleshooting / narrowing down the cause? If not, which one is? Netdev or some other? * What specific info is needed? Already gathered is output from "ip rule list", "ip route show table" for the various tables and "ip route show cache", both with kernel 2.6.38 and kernel 2.6.39. Thanks in advance for any advice, insights or assistance. Regards, Jeroen van Ingen ICT Service Centre University of Twente, P.O.Box 217, 7500 AE Enschede, The Netherlands Telephone +31 53 489 2526, Fax +31 53 489 2383 J.vanIngenSchenau@utwente.nl; http://www.utwente.nl/icts