Re: Best way to deal with bad advertisements?

[Avi Freedman <freedman () netaxs com>]

> >   Hi Matt,
> >
> > > > In this case, the very first thing you should probably do is to
> > > > start announcing the more specific /24s to match their advertisements!
> > > > Depending on AS-PATH length (how various nets hear your announcements
> > > > vs. theirs) this may solve the immediate problem, allowing you to hunt
> > > > them down and kill them at your leisure.
> > >
> > > The downside to this is that we go from advertising /16's
> > > out, to advertising a fleet of /24's out, most of which 
> > > would be filtered by Sprint's ever-lovin' CIDR-forcing
> > > wall.  
> >
> >   If your more specific networks are filtered, then wouldn't the
> >   evil ISP's be filtered as well?
> >
> >   This would be a large problem only if you gain transit from Sprint....
>
> Bingo.  We buy transit from Sprint.

It's the other way around:  You are safe.

Because you buy transit from Sprint, Sprint WILL hear your more specifics.
Sprint will NOT hear more specifics from peers, customers of peers, 
customers of customers of peers, etc...

> > > I agree with Sprint, and Sean, but in this case
> > > it pretty much makes it hard for us to force the issue
> > > by dropping to the same or smaller sized announcement.
> >
> >   Well, I'm not sure that the two entities can be put in the 
> >   same sentence any more, but you can always leave the less specific
> >   /16 in there while you attempt to advertise the more speciic.
>
> Good point; I'd forgotten you can have both advertised, and
> those that hear the /16, and no /24's will honor it, those
> that hear the /24's get to worry about the weights independantly
> of the /16's advertisement.

Specificity wins.  

> Matt

Avi
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