Deciding whose network block is whose?

Geoff Huston gih at
Tue Jan 6 19:59:03 UTC 1998

At 11:13 AM 1/6/98 -0800, Sean M. Doran wrote:
>Geoff Huston <gih at> writes:
>> I am looking to the regional registeries to take some level of initiative 
>> and provide clients of their address allocation service the ability to 
>> sign the allocation and then the client can sign the routing request to the
>> provider which the provider can verify against the regional registry.
>> We went through this in discussion in the room at the time and it
>> looked like a viable and useful approach.
>Yes, but this is only part of the problem.
>I mean, fantastic idea, but then it's not exactly
>transitive.  How do I know I can trust that Telstra's
>announcements have been authorized by the people
>responsible for the prefixes in question?  Worse, since I
>do not talk directly with Telstra, how do I know I can
>trust the intermediary networks not to have performed (or
>fallen victim to) AS path surgery?
>Moreover, other than prefix-length filtering, what can I
>do to prevent falling victim to subnet-announcement
>attacks?  Note that a larger CIDR block can still fall
>victim to announcements of /19s in networks which use The
>Satanic Filters.
>Perhaps you have some idea other than mine (prayer) for
>scalably solving these and similar issues?

My point was that one direction of addressing Sean Donelan's
original problem was to clearly identify the point in the network 
where the announcement is originated and clearly
identify the legitimacy of each advertisement incrementally
through  the use of explicit signatures. It does not address
explicitly the issue of routing policy at a distance, which you
identify as a bloody big scaling problem - and I agree that it is!


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