From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nivedita Singhvi Subject: Re: peth1: received packet with own address as source address Date: Mon, 17 Oct 2005 14:32:01 -0700 Message-ID: <43541851.6020503@us.ibm.com> References: <1129574685.6253.20.camel@dbarrera_tp> <4353F277.3080703@yahoo.de> <1129580110.6252.28.camel@dbarrera_tp> <435409BE.1070006@yahoo.de> <435411F0.6030401@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <435411F0.6030401@us.ibm.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Andrew Theurer Cc: David F Barrera , xen-devel , Arnd Schmitter List-Id: xen-devel@lists.xenproject.org Andrew Theurer wrote: > Arnd Schmitter wrote: > >> David F Barrera wrote: >> >>> On Mon, 2005-10-17 at 20:50 +0200, Arnd Schmitter wrote: >>> >>> >>>> David F Barrera wrote: >>>> >>>> >>>>> peth1: received packet with own address as source address >>>>> >>>>> Is this something that I should care about? I don't see an obvious >>>>> impact to the machine. >>>> >>>> >>>> This means normaly two things: Packets you send out are returning or >>>> there is another PC with the same address. >>>> The Linuxkernel drops this packets as he think its a knd of address >>>> spoofing. >>>> If all networking is working fine you will only have a minimal >>>> impact on performance. But it could indicate that something with >>>> your network configuration is wrong >>>> >>> >>> >>> Arnd, thanks for your response. My network configuration appears to be >>> OK; it is simple, one NIC and its IP address, and everything seems to be >>> working well. Also, there are no two machines with the same address. So, >>> I am wondering if this is a problem with Xen. I have opened up a >>> bugzilla report, as I would like to have a definitive answer as to >>> whether this is a bug or a network configuration issue. >>> >>> http://bugzilla.xensource.com/bugzilla/show_bug.cgi?id=339 >>> >> >> >> >> Only one NIC and peth1 ?? >> >> Take a look at your ifconfig output. Maybe there are two >> Virtual-Interfaces witch the same MAC. > > > Unless the network-bridge script has changed the generated mac for eth0 > (which gets renamed to peth0), all systems probably have the same mac > for peth0 & xen-br0: fe:ff:ff:ff:ff:ff. I have tried using unique macs > (for just peth0, vif0.0, and xen-br0, other vifs still have fe:ff...), > and these messages disappear. So, why would the mac for a veth0 or > xen-br0 get sent to another system? Not sure, since they should not > have an ip address, and should not respond to an arp request. I do > notice that peth0 has 'noarp' but xen-br0 does not. Perhaps adding > noarp to xen-br0 will fix this. This is what I thought it was, until Anthony said he was seeing it even without guest domains, and without xend starting. I'd thought the network rename was in vif-bridge, but misremembered, it's in network-bridge, so it really doesn't need xend to run to run into the problem. The MAC address is expected to be unique in a network, so it is a problem if it's not. The non-public MAC should not be going out, and if someone could just say which the "same MAC address" reported in the message is, that would confirm it. But xen-br0 shouldn't need a noarp(?) (checking...) thanks, Nivedita