nanog mailing list archives

Re: Apple devices spoofing default gateway?


From: Matt Freitag <mlfreita () mtu edu>
Date: Fri, 7 Jun 2019 15:59:26 -0400

For those of us with Aruba wireless, www boy, could you share some more
info about your setup/code version/configuration/specific APs/controller
model(s)/etc?

Matt Freitag
Network Engineer
Michigan Tech IT
Michigan Technological University

We can help.
mtu.edu/it
(906) 487-1111


On Fri, Jun 7, 2019 at 3:06 PM Matt Hoppes <
mattlists () rivervalleyinternet net> wrote:

Turn on client isolation on the access points?

On Jun 7, 2019, at 3:00 PM, Hugo Slabbert <hugo () slabnet com> wrote:


On Fri 2019-Jun-07 16:21:29 +1000, www boy <wwwboy () gmail com> wrote:

I just joined nanog to allow me to respond to a thread that Simon
posted in
March. .
(Not sure if this is how to respond)

We have the exact same problem with Aruba Access points and with
multiple
MacBooks and a iMac.
Where the device will spoof the default gateway and the effect is that
vlan
is not usable.

I also have raised a case with Apple but so far no luck.

What is the status of your issue?  Any luck working out exactly what the
cause is?

We appeared to hit this with Cisco kit:

https://www.cisco.com/c/en/us/support/docs/wireless/aironet-3800-series-access-points/214491-arp-responses-for-default-gateway-ip-add.html

They don't say *exactly* that the Apple devices are spoofing the
gateway, but some behaviour in what they send out results in the proxy arp
being performed by the APs to update the ARP entry for the gateway address
to the clients':

* This is not a malicious attack, but triggered by an interaction
between the macOS device while in sleeping mode, and specific broadcast
traffic generated by newer Android devices
* AP-COS while in FlexConnect mode provides Proxy ARP (ARP caching)
services by default.  Due to their address learning design, they will
modify table entries based on this traffic leading to default gateway ARP
entry modification

The fix was to disable ARP caching on the APs so they don't proxy ARP
but ARP replies pass directly between client devices.

--
Hugo Slabbert       | email, xmpp/jabber: hugo () slabnet com
pgp key: B178313E   | also on Signal


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