Automatic IPv6 due to broadcast
owen at delong.com
Mon Apr 23 08:38:09 CDT 2012
On Apr 23, 2012, at 6:25 AM, Chuck Anderson wrote:
> 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.
In a lot of cases, enforcing that all address assignments are via DHCP can still be
counter-productive. Especially in IPv6.
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