Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-la0-f53.google.com ([209.85.215.53]:55763 "EHLO mail-la0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751010AbaAOL5j (ORCPT ); Wed, 15 Jan 2014 06:57:39 -0500 Received: by mail-la0-f53.google.com with SMTP id e16so1328100lan.12 for ; Wed, 15 Jan 2014 03:57:37 -0800 (PST) MIME-Version: 1.0 Date: Wed, 15 Jan 2014 03:57:37 -0800 Message-ID: Subject: unable to send TCP SYNs from ports lower than 1024 From: Stuart Kendrick To: linux-nfs@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: Is anyone else seeing this? This issue prevents NFS client mounting, since the NFS client wants to use source ports below 1024 Linux ubuntu 3.8.0-35-generic #50~precise1-Ubuntu SMP Wed Dec 4 17:25:51 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux As I analyze, I use netcat plus wireshark to validate, with wireshark running on both the client machine and on a second machine plugged into the local Ethernet switch's SPAN port This invocation produces outbound TCP SYNs in both traces: ubuntu# nc -4 -p 1024 10.1.1.1 2049 Whereas this invocation produces TCP SYNs only in the on-board pcap -- the pcap taken from the switch's SPAN port contains nothing (well, it contains the ARP exchange with10.1.1.1, but no TCP frames). ubuntu# nc -4 -p 1023 10.1.1.1 2049 I have some evidence to suggest that it appeared in 3.8.0-33 or higher --sk Stuart Kendrick