I wonder if anybody else have seen this problem. In the past two weeks we've had two cases where a "tethering" between a MacBook and an iPhone have resulted in some strange "loop" on the network.
It seems that the users have setup some kind of network connection sharing between the iPhone and the Mac. I don't know Macs well enough to know exactly how it works, but it looks like some NAT thing. It also looks like the Mac uses a wired connection and the iPhone uses a wireless connection to the same L2 network. On the gateways (running HSRP) we then see this: 002660: May 21 09:16:50.426 CEST: %HSRP-4-BADAUTH: Bad authentication from 10.100.0.134, group 22, remote state Standby It turns out this (10.100.0.134) is the IP address of the MacBook. Capturing the traffic, we can see that it is exactly the HSRP hellos, but just with the IP address replaced, a la NAT. Without HSRP authentication (we tried that too!) it actually "steals" the primary role, i.e. when it "reflects" the primary router's hello the two real routers assume a "Standby" role. It doesn't cause broadcast loops or anything, so it seems to only forward/bridge unicast packets. Apart from telling people not to connect their wonderful Apple devices in this way, what can we do? :-) -- Peter _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
