Suspecious anycast prefixes

David Miller dmiller at
Thu May 5 13:43:52 UTC 2011

On 5/5/2011 8:59 AM, Danny McPherson wrote:
> On May 3, 2011, at 6:17 AM, Bill Woodcock wrote:
>> Hash: SHA1
>> On May 2, 2011, at 12:35 PM, Joe Abley wrote:
>>> It's perhaps worth noting that there is work in the IETF to recommend that every prefix originated as part of an anycast cloud uses a unique origin AS (see<>). I'm not personally convinced of the arguments in the draft, but mentioning it in this thread seems reasonable.
>> I'm also not convinced of the arguments in the draft, since it argues that it would be a best-practice
> 'A', not 'the', for the reasons conveyed in the draft (e.g., control
> plane discriminator, RPKI foundations, etc..).  If you don't like it,
> don't do it, it's certainly easier to not do it.
>> for me to originate my address space from more than 8,000 different ASNs,
> 8000 is a very large number.
>> when I currently do just fine advertising it from three.
> "You" as a service operator do just fine, and it's surely much
> simpler from a configuration and provisioning standpoint.  But
> what about those folks that consume the service, and have no
> indication of which node they may be utilizing from an Internet
> control plane perspective, or all the associated derivatives?

In a properly functioning system - folks that consume the service don't 
need to know which node they are utilizing.

Providing the capability for well behaved customers to select/prefer a 
particular node over another would also allow evildoers to select/prefer 
a particular node over others - thereby increasing the attack surface of 
this node, yes?

Not a fan.

>>   I'd much rather there not exist a document that clueless people can point at and claim is a "best common practice" when it's neither best nor common.
> 'clueless people' wouldn't care which node they utilize, where
> it resides, or what other attributes might exist and be associated
> with it.  Providing a discriminator in the control plane for the
> consumer of critical network services might well be of utility to
> some.
> -danny

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