BGP prefix filter list

William Herrin bill at
Fri May 24 20:25:34 UTC 2019

On Fri, May 24, 2019 at 11:34 AM Blake Hudson <blake at> wrote:

> William Herrin wrote on 5/24/2019 1:22 PM:
> >  If you drop the /24, you break the Internet when my connection to
> > CenturyLink is inoperable.
> Not really. The remote networks that drop visibility to your /24
> announcement still have a default route. They just just leave the
> decision of the best path to your /24 up to their upstream provider(s)
> rather than having direct knowledge.

If you're talking about a leaf node in the BGP system then sure. You can
ditch whatever you want and replace it with default routes. Ditch whole
/8's if it floats your boat. Partial feed has always been acceptable for
leaf nodes.

If you're talking about a transit node then no, you're breaking the
Internet. Even if you have a default route, your downstream customer, to
whom you fail to provide the /24, will suffer malfunction.

Bill Herrin

William Herrin
bill at
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