From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?ISO-8859-1?Q?Ortwin_Gl=FCck?= Subject: is UDP broadcast over wlan broken? Date: Sun, 22 May 2011 16:30:46 +0200 Message-ID: <4DD91E16.1070300@odi.ch> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org Return-path: Received: from fep22.mx.upcmail.net ([62.179.121.42]:50783 "EHLO fep22.mx.upcmail.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755133Ab1EVOlu (ORCPT ); Sun, 22 May 2011 10:41:50 -0400 Sender: netdev-owner@vger.kernel.org List-ID: Hi, On 2.6.38.6 I can no longer receive UDP broadcasts over wireless interfaces. This affects CUPS zeroconf (port 631 broadcasts). Other UDP traffic (like DNS lookups) works fine. I can see UDP broadcasts originate fine on 192.168.111.11/24 (my router): # uname -a Linux gandalf 2.6.38.6 #11 SMP PREEMPT Tue May 10 13:42:44 CEST 2011 x86_64 Intel(R) Core(TM) i3 CPU 540 @ 3.07GHz GenuineIntel GNU/Linux # tcpdump -np -i wlan0 udp and port 631 tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on wlan0, link-type EN10MB (Ethernet), capture size 96 bytes 16:15:21.695230 IP 192.168.111.11.631 > 192.168.111.255.631: UDP, length 151 But these packets are not received on 192.168.111.10/24 (the client): # uname -a Linux mithril 2.6.39 #2 SMP PREEMPT Sun May 22 14:22:23 CEST 2011 i686 Intel(R) Core(TM)2 CPU T7600 @ 2.33GHz GenuineIntel GNU/Linux # tcpdump -n -i wlan0 udp and port 631 tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on wlan0, link-type EN10MB (Ethernet), capture size 96 bytes ^C 0 packets captured 0 packets received by filter 0 packets dropped by kernel I made very sure that nothing is dropped by netfilter on either side. Both sides use ath9k as their wifi driver. Ortwin