[ppml] [address-policy-wg] Those pesky ULAs again

[Per Heldal]

On Wed, 2007-05-30 at 10:48 -0400, Marshall Eubanks wrote:
> On May 30, 2007, at 4:33 AM, Per Heldal wrote:
> 
> > If you want to endorse PI for "private" use please also consider  
> > that it
> > leaves blocks wide open to abuse. Separate ULA-C space can easily be
> > filtered, but how do you easily prevent hijacking of unannounced
> > PI-prefixes should such private blocks become as commonplace as
> > rfc1918-space?
> 
> How do you prevent it now, in IPv4 ? 

I filter private addresses ;)  (rfc1918).

> (I know several companies with  
> addressable blocks for
> internal use, and so I suspect that this is not that rare.)

I expect those relatively few with "hidden" V4 PI to be elegible for V6
PI and that they will continue a similar practise with V6. My concern is
directed at those who promote unannounced public V6 blocks as a
mass-replacement for rfc1918 when efforts imho are better spent on
solutions to eliminate the use of NAT and private space. 

Btw, holding back part of a PI block is also going to create problems.
>From a transit-provider perspective I find it reasonable to filter
anything smaller than RIR-allocated blocks . I.e. anything longer than
a /48 from PI-land is filtered. A couple extra bits may be accepted if
the as-path-length is 2 or less (for TE purposes). Similar goes for
PA-land. Where does that leave a /48 split split up to keep parts of it
"secret"?


//per