From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6376BC282CD for ; Tue, 29 Jan 2019 00:45:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2F72B214DA for ; Tue, 29 Jan 2019 00:45:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727026AbfA2Apr (ORCPT ); Mon, 28 Jan 2019 19:45:47 -0500 Received: from mail.grenz-bonn.de ([178.33.37.38]:34428 "EHLO mail.grenz-bonn.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726803AbfA2Apr (ORCPT ); Mon, 28 Jan 2019 19:45:47 -0500 Received: from [192.168.1.100] (212-51-139-180.fiber7.init7.net [212.51.139.180]) by ks357529.kimsufi.com (Postfix) with ESMTPSA id 7D38F628FC; Tue, 29 Jan 2019 01:45:45 +0100 (CET) Subject: Re: Packets being dropped somewhere in the kernel, between iptables and packet capture layers To: netdev@vger.kernel.org Cc: Florian Westphal References: <19e1b7a2-00b2-3656-309c-0586e990007b@nh2.me> <20190128062121.fbksn2vdzpthwfkh@breakpoint.cc> From: =?UTF-8?Q?Niklas_Hamb=c3=bcchen?= Message-ID: <59bc1935-a3b3-dcf8-2db1-f9a90bd348d4@nh2.me> Date: Tue, 29 Jan 2019 01:45:44 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190128062121.fbksn2vdzpthwfkh@breakpoint.cc> Content-Type: text/plain; charset=iso-8859-15; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org > Some DNS requests on my machine take 5 seconds when a specific network interface is used. My big apologies for the confusion. I have found the reason. There was a scripted tc qdisc add dev enp3s0 root netem loss 5% in effect that I wasn't aware of while investigating. This dropped 5% of the packets, and also explains why it was on that interface only. Well, at least I know very well now at which level `tc` operates. My bad, and sorry for the noise.