Inbound prefix filters

John A. Tamplin jat at
Tue Nov 11 17:36:11 UTC 1997

On Tue, 11 Nov 1997, Phil Howard wrote:

> Sean M. Doran writes...
> [re: inbound filtering]
> > Sprintlink did at one point.  It's a really good idea to do
> > this in general because it mitigates the disconnectivity
> > customers assigned prefixes out of one's address blocks
> > will suffer if and when someone accidentally(?) announces
> > subnet of those blocks.
> Good point.

Actually, I view it the other way.  If someone is announcing routes for one
of our prefixes, connectivity is at least partially broken for that prefix,
and I want to know about it sooner rather than later.  If I see an 
advertisement for that route in our router, I can tell quickly who I need
to call.

BTW, this has happened to us twice, and both times the offender was a 
direct competitor in one of our local markets.  Does anybody have any 
feel for how often these "accidents" are not accidents?

John Tamplin					Traveller Information Services
jat at Traveller.COM				2104 West Ferry Way
205/883-4233x7007				Huntsville, AL 35801

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