From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next] net: ipv4: Add ability to have GRE ignore DF bit in IPv4 payloads Date: Fri, 10 Jun 2016 23:02:02 -0700 (PDT) Message-ID: <20160610.230202.897629473050684544.davem@davemloft.net> References: <20160607194846.11494-1-philipp@redfish-solutions.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, stephen@networkplumber.org To: philipp@redfish-solutions.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:35102 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751043AbcFKGCE (ORCPT ); Sat, 11 Jun 2016 02:02:04 -0400 In-Reply-To: <20160607194846.11494-1-philipp@redfish-solutions.com> Sender: netdev-owner@vger.kernel.org List-ID: From: "Philip Prindeville" Date: Tue, 7 Jun 2016 13:48:46 -0600 > From: Philip Prindeville > > In the presence of firewalls which improperly block ICMP Unreachable > (including Fragmentation Required) messages, Path MTU Discovery is > prevented from working. > > A workaround is to handle IPv4 payloads opaquely, ignoring the DF bit--as > is done for other payloads like AppleTalk--and doing transparent > fragmentation and reassembly. > > Reviewed-by: Stephen Hemminger > Signed-off-by: Philip Prindeville I think the feedback that this feature should be mutually exclusive to pmtudisc is valid and you should address that.