all the mails on Filtering

Wed Nov 13 18:36:52 UTC 2002

	If you're multihomed you can generally obtain provider indepdent
space from your RIR.

	Most people who do this filtering do it on the RIR boundaries
for their minimum allocation.

	If you are annoucing your provider assigned space 
as a /24, they tend to announce the (/14 - /rir-minimum)
so your packets will follow the aggregate.  If they
are not announcing their aggregate then you will have
problems.  Most people in that case would blame
the provider for not announcing their space.

	- Jared

On Wed, Nov 13, 2002 at 10:25:53AM -0800, Harsha Narayan wrote:
> 
> Hi,
> 
>   So what happens to multihoming assignments made by the ISP? That means
> the multihoming assignment can't be used as a backup. If the customer's
> connection to the ISP which made the multihoming assignment gets lost,
> then it can't use its multihoming assignments (say a /24) to get traffic
> from some other ISP?!
> 
> Thanks to all,
> Harsha.
> 
> On Wed, 13 Nov 2002, Buddy Bagga wrote:
> 
> > Greets,
> >
> > Look at <http://www.nanog.org/filter.html>. If I remember correctly, Verio
> > used to filter prefixes longer than /19s in classful A range. Apparently
> > this isn't the case anymore. But it would be naive to think that ISP only
> > filter prefixes longer than /24.
> >
> > 	Cheers,
> >
> > On Wed, 13 Nov 2002, Harsha Narayan wrote:
> >
> > >    Are there some ISPs who filter prefixes longer than /19 or a /20?. I
> > > thought they filtered only prefixes which are longer than /24?
> >
> > ~
> > Buddy Bagga
> > Genuity | BBN
> >
> 

-- 
Jared Mauch  | pgp key available via finger from jared at puck.nether.net
clue++;      | http://puck.nether.net/~jared/  My statements are only mine.