Route table growth and hardware to the filter

Stephen Sprunk stephen at
Mon Sep 10 21:54:54 UTC 2007

Thus spake "Kevin Loch" <kloch at>
> Stephen Sprunk wrote:
>> Sucks to be them.  If they do not have enough PA space to meet
>> the RIR minima, the community has decided they're not "worthy"
>> of a slot in the DFZ by denying them PI space.
> Not true, there is an ARIN policy that allows you to get a /24 from
> one of your providers even if you only need 1 IP address:
> "This policy allows a downstream customer's multihoming
> requirement to serve as justification for a /24 reassignment from
> their upstream ISP, regardless of host requirements."

If the PA /24 is under 199/8 or 204-207/8, then the filters being discussed 
would allow their advertisement through, because ARIN's minimum allocation 
for those blocks is /24.  In ARIN's 22 other /8s, the filters would not 
because the minimum is /20 (or /22, for 208/8).

Let's also keep in mind that if other folks block a PA more-specific, the 
site doesn't lose connectivity unless they lose their upstream connection to 
the LIR that assigned them the block.  I suspect that many of them already 
see that behavior today, at least partially; we're really discussing making 
it a near-complete outage versus a semi-outage.  That's life if you don't 
qualify for a real routing slot via PI.


Stephen Sprunk         "God does not play dice."  --Albert Einstein
CCIE #3723         "God is an inveterate gambler, and He throws the
K5SSS        dice at every possible opportunity." --Stephen Hawking 

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