From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Greear Subject: Re: ppp and routing table rules. Date: Thu, 01 Mar 2007 22:29:51 -0800 Message-ID: <45E7C45F.9080805@candelatech.com> References: <45E7AC31.9030309@candelatech.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: NetDev Return-path: Received: from ns2.lanforge.com ([66.165.47.211]:35987 "EHLO ns2.lanforge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422963AbXCBG1t (ORCPT ); Fri, 2 Mar 2007 01:27:49 -0500 Received: from [71.112.198.166] (pool-71-112-198-166.sttlwa.dsl-w.verizon.net [71.112.198.166]) (authenticated bits=0) by ns2.lanforge.com (8.13.4/8.13.4) with ESMTP id l226Rnqx006529 for ; Thu, 1 Mar 2007 22:27:49 -0800 In-Reply-To: <45E7AC31.9030309@candelatech.com> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Ben Greear wrote: > Hello! > > I have a suspicion (but no proof at this time) that a rule like this: > > 20: from all iif ppp400 lookup 10001 > > is not actually working for ppp interfaces. Before I go adding printk > statements, are there any > stats that would show if packets are hitting a particular rule or > routing table? Ok, the rule is working and the routing table is being used. But, weirdness abounds. Here is my setup: I have ppp401 (11.1.1.3/32) connected to ppp400 (11.1.1.2/32), over a cross-over T1 NIC (ie, this is going to the same machine). Anything coming in on ppp400, uses a particular routing table, whose routes look like this: 10.1.1.3 via 172.1.2.2 dev rddVR4 11.1.1.2 via 11.1.1.2 dev ppp400 172.1.2.0/24 via 172.1.2.1 dev rddVR4 172.1.1.0/24 via 172.1.2.2 dev rddVR4 10.0.0.0/8 via 172.1.2.2 dev rddVR4 11.0.0.0/8 via 11.1.1.2 dev ppp400 default via 11.1.1.2 dev ppp400 If all worked as planned, the packets would traverse several other routing tables, the final which has another pair of ppp links in it (ppp200, 10.1.1.2/32 connected to ppp201, 10.1.1.3/23). I am sending udp packets through ppp400, and I see them appear on ppp401 as expected. The thing that is bothering me is that all I see on rddVR4 (172.1.2.1) is arps for 172.1.2.2, but the 'tell' IP is that of the originating ppp400 link, not the IP of rddVR4, as I expected: 21:47:16.119640 arp who-has 172.1.2.2 tell 11.1.1.3 21:47:17.119371 arp who-has 172.1.2.2 tell 11.1.1.3 21:47:18.119254 arp who-has 172.1.2.2 tell 11.1.1.3 21:47:19.273118 arp who-has 172.1.2.2 tell 11.1.1.3 Unless I'm missing something dumb, a similar setup with all ethernet-ish network devices works fine. I have also enabled arp filtering: # Only answer ARPs if it is for the IP on our own interface. echo 2 > /proc/sys/net/ipv4/conf/all/arp_ignore and for every device used in these routing tables: echo 1 > /proc/sys/net/ipv4/conf/[dev]/arp_filter Any idea what I need to do in order to make the source IP for the ARP packet correct? Thanks, Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com