[152274] in North American Network Operators' Group
Re: Automatic IPv6 due to broadcast
daemon@ATHENA.MIT.EDU (Chuck Anderson)
Mon Apr 23 09:26:09 2012
Date: Mon, 23 Apr 2012 09:25:25 -0400
From: Chuck Anderson <cra@WPI.EDU>
To: nanog@nanog.org
Mail-Followup-To: nanog@nanog.org
In-Reply-To: <432EAB18-387A-4EC3-8901-49A990FFAC7A@delong.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Mon, Apr 23, 2012 at 12:24:53AM -0700, Owen DeLong wrote:
> On Apr 22, 2012, at 10:30 PM, Jimmy Hess wrote:
> > Particularly good L2 switches also have
> > DAI or "IP Source guard" IPv4 functions, which when properly
> > enabled, can foil certain L2 ARP and IPv4 source address spoofing
> > attacks, respectively.
> >
>
> > e.g. Source IP address of packet does not match one of the DHCP leases
> > issued to that port -- then drop the packet.
> >
>
> Meh... I can see many cases where that might be more of a bug than feature.
>
> Especially in environments where loops may be possible and the DHCP lease might
> have come over a different path than the port in question during some network event.
You're only supposed to use those features on the port directly
connected to the end-system, or to a few end-systems via an unmanaged
office switch that doesn't have redundant uplinks. I.e. edge ports.
