Date: Mon, 05 Feb 2001 22:00:21 -0800 From: Julian Elischer <julian@elischer.org> To: Rich Wales <richw@webcom.com> Cc: Luigi Rizzo <rizzo@aciri.org>, patrick@netzuno.com, freebsd-net@FreeBSD.ORG, julian@FreeBSD.ORG Subject: Re: Almost fixed (was Re: BRIDGE breaks ARP? (Julian's patch)) Message-ID: <3A7F92F5.A5C7971F@elischer.org> References: <20010206003554.78441.richw@wyattearp.stanford.edu>
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Rich Wales wrote: > > I wrote: > > > > ARP replies from the bridge to the DSL modem (via the > > > external i/f) are still getting sent to the desktop > > > (via the internal i/f), > > Luigi replied: > > > this is a bit less expected -- because the reply is unicast to > > the MAC of the host requesting the packet, and ether_output() > > is called with the correct interface pointer. What do you have > > in net.link.ether.bridge_cfg, and do you also see the ARP reply > > on the 'external' side (i suppose so) ? > > net.link.ether.bridge_cfg: rl0:1,xl0:1,pcn0:2,ed0:2, > > I'm running two clusters. rl0/xl0 (using public IP addresses) is the > one that's been involved in all the bugs I've been reporting. pcn0/ed0 > (using private IP addresses) is for our children's computers. > > And yes, as far as I'm aware, the ARP reply is being seen by the DSL > modem on the "external" side of the rl0/xl0 cluster. I did some tests > last night with "tcpdump" to confirm this. If absolutely necessary, > I could probably bring a laptop home from work, hook it up to the > external segment (alongside the DSL modem), and run "tcpdump" on said > laptop to further confirm what's showing up out there. > What is happenning (I THINK) is that the original arp request is received on both interfaces, (it's being bridged) and two replies are sent. The last one received is taken as being true, and that is the one that came through the internal interface, and this gives that address. Both replies are sent out the 'external interface, because the bridge code knows that that is where the target is. From then on the modem will use the address of the internal address. It should still work fine though. Netgraph bridging would not have a prolem with this because there is only one interface to the system which connects to the entire bridged network and all traffic to and from the bridged network is seen as passing through that interface from the system point of view. > Rich Wales richw@webcom.com http://www.webcom.com/richw/ -- __--_|\ Julian Elischer / \ julian@elischer.org ( OZ ) World tour 2000-2001 ---> X_.---._/ v To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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