Announcing a reserved ASN?

Richard Barnes richard.barnes at gmail.com
Sun Feb 3 18:58:13 UTC 2013


Some links:
http://www.nanog.org/meetings/nanog45/presentations/Tuesday/Hankins_4byteASN_N45.pdf
https://tools.ietf.org/html/rfc6793


On Sun, Feb 3, 2013 at 11:15 AM, Brandon Ross <bross at pobox.com> wrote:

> I strongly recommend that you read about and fully understand how 4-byte
> ASNs work, and their use of AS23456 before you continue this thread.
>
>
> On Sun, 3 Feb 2013, Suresh Ramasubramanian wrote:
>
>  I do believe, as has been pointed out to me elsewhere that this is what
>> shows up when there's a 64 bit ASN and router software that doesn't grok
>> 64
>> bit ASNs
>>
>> So, completely by chance that one such as belongs to what looks like a
>> bulk
>> mailer
>>
>> --srs (htc one x)
>> On 03-Feb-2013 9:02 PM, "Dave Pooser" <dave.nanog at alfordmedia.com> wrote:
>>
>>  On 2/3/13 9:04 AM, "Rich Kulawiec" <rsk at gsp.org> wrote:
>>>
>>>  On Sun, Feb 03, 2013 at 06:12:32PM +0530, Suresh Ramasubramanian wrote:
>>>>
>>>>> AS23456 is currently announcing a good few netblocks (which don't have
>>>>> a
>>>>> very good smtp reputation, by the way).
>>>>>
>>>>
>>>> To say the least.  A quick rDNS scan reveals that those netblocks
>>>> include:
>>>>
>>>>       8448  addresses
>>>>       6932  return nxdomain
>>>>       512   return servfail
>>>>       1004  with rDNS entries
>>>>
>>>> Those 1004 hosts with rDNS account for 36 domains:
>>>>
>>>
>>> <snip long list of spammy domains>
>>>
>>> Just as another data point, the domain names you listed hit on enough URL
>>> blacklists that Spamassassin quarantined the message for me (and would
>>> have rejected it during the SMTP transaction had the NANOG server not
>>> been
>>> listed on DNSWL-High). Spam hosts plus fake ASN = paging the Spamhaus
>>> DROP
>>> maintainers to the white courtesy phone....
>>> --
>>> Dave Pooser
>>> Manager of Information Services
>>> Alford Media  http://www.alfordmedia.com
>>>
>>>
>>>
>>>
>>>
>>
> --
> Brandon Ross                                      Yahoo & AIM:
>  BrandonNRoss
> +1-404-635-6667                                                ICQ:
>  2269442
> Schedule a meeting:  https://doodle.com/bross            Skype:
>  brandonross
>
>



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