Charter ARP Leak

Jason Hellenthal jhellenthal at dataix.net
Tue Dec 30 01:38:07 UTC 2014


Well sure they are subnets :-) of 0.0.0.0/4

range:       0.0.0.0 > 15.255.255.255
range b10:   0 > 268435455
range b16:   0x0 > 0xfffffff
hosts:       268435456
prefixlen:   4
mask:        240.0.0.0

Doubt anyone should ever describe them as such unless they own all that space though. May God rest their soul if they do.

> On Dec 29, 2014, at 19:21, Larry Sheldon <larrysheldon at cox.net> wrote:
> 
> On 12/29/2014 11:35, Brett Frankenberger wrote:
>> On Mon, Dec 29, 2014 at 12:27:04PM -0500, Jay Ashworth wrote:
>>>> 
>>>> Valdis, you are correct. What your seeing is caused by multiple IP
>>>> blocks being assigned to the same CMTS interface.
>>> 
>>> Am I incorrect, though, in believing that ARP packets should only be visible
>>> within a broadcast domain,
>> 
>> broadcast domain != subnet
> 
> It surprises me that in this day and age, in a forum like this that has an active thread about kids being taught archaic concepts, we see language like "broadcast domain != subnet" and a perceived need to explain it.
> 
> [no longer germane material deleted to reduce excess baggage charges]
> 
>> int ethernet 0/0
>>   ip address 10.0.0.1 255.255.0.0
>>   ip address 11.0.0.1 255.255.0.0 secondary
>>   ip address 12.0.0.1 255.255.0.0 secondary
>> 
>> The broadcast domain will have ARP broadcasts for all three subnets.
> 
> This are not "subnets"!  They are IP addresses in three different IP networks.
> 
>> Doing it over a CMTS doesn't change that.
> 
> Communication here perceived as hostile is apologized-for.
> 
> 
> -- 
> The unique Characteristics of System Administrators:
> 
> The fact that they are infallible; and,
> 
> The fact that they learn from their mistakes.
> 
> 
> Quis custodiet ipsos custodes

-- 
 Jason Hellenthal
 Mobile: +1 (616) 953-0176
 jhellenthal at DataIX.net
 JJH48-ARIN




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