Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031304AbXECUxp (ORCPT ); Thu, 3 May 2007 16:53:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1031325AbXECUxp (ORCPT ); Thu, 3 May 2007 16:53:45 -0400 Received: from 1wt.eu ([62.212.114.60]:2474 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031304AbXECUxo (ORCPT ); Thu, 3 May 2007 16:53:44 -0400 Date: Thu, 3 May 2007 22:53:41 +0200 From: Willy Tarreau To: =?iso-8859-1?Q?=D8yvind_V=E5gen_J=E6gtnes?= Cc: Linux Kernel Mailing List Subject: Re: Routing 600+ vlan's via linux problems (looks like arp problems) Message-ID: <20070503205341.GB943@1wt.eu> References: Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1574 Lines: 37 On Thu, May 03, 2007 at 10:25:48PM +0200, ?yvind V?gen J?gtnes wrote: > Hi, > > We have a one gigabit internet connection that is normally > routed by a hardware juniper router. The drive in this is down > and we need to use a linux machine (Pentium D 3 ghz) as a > temporary router. > Now setting up all the 600 vlans and assigning ip addresses > is no problem. We have testet all by using a laptop, setting up > 600 vlan interfaces on this and running dhcpclient on all. > This worked just fine, all the interfaces got address. > > Now for the real setup. > We closed the mac of the juniper to the network card that > would be connected to the internal LAN, set up the interfaces, > and swapped cables. This worked fine for approximately 100 > of the computers that are connected, but the rest would not > get IP. The connected 100 computers were routed just fine. > > What we think the problem is, is that the arp cache on the > linux router seems strange. It can resolve the MAC for the > 100 clients that actually got through. > For the rest all we see in the arp cache is (incomplete) I suspect that your arp cache is full (128 entries by default). Check /proc/sys/net/ipv4/neigh/gc_thresh1 (128 for me). You can set it as high as gc_thresh2 (512 for me), and I don't know what happens above. Hoping this helps, Willy - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/