On Tue, 28 Nov 2006 11:01:20 -0800 "Tim Wright" <timw@xxxxxxxxxxxxx> wrote: > Hi folks, > I have been tracking down a strange problem, and have a simple > "reproduce-by" and was looking for opinions from those better-versed in > the networking code. Basically, it is possible to get a system into a > state where it responds to ARP requests even though no interface has the > address requested. Here is a simple reproduce-by: > > Select and address in the same subnet as eth0 > # ifconfig eth0:5 W.X.Y.Z netmask ... up > This works. Machine now responds to arp requests for W.X.Y.Z. > # ifconfig eth0:6 W.X.Y.Z netmask ... up > This fails as it should. But, the damage is done. > # ifconfig > You will only see eth0 and eth0:5. There is no eth0:6 interface. Good. > # ifconfig eth0:5 down > Now we are supposedly back to the original state. BUT the machine will > still respond to ARP requests for W.X.Y.Z > > The easiest way to get out of this is to bring up eth0:5 again, and > bring it down again. However, this looks to me like the undo code when a > clashing address is found fails to clean up the arp side of things > correctly. Any clues here? > > Please copy me on any responses. I am not on the linux-net mailing list. > > Thanks very much, This is a common confusion. Read the mailing list archives. Linux associates IP address with system not interface, so it will respond to ARP for any of the IP addresses on any interface. - To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
