[c-nsp] BGP Route Announcement

[Shawn L]

That second part has bit me in the rear before..... As a matter of course
now I always make a static route to null 0 for every prefix I announce via
BGP.  Once I verify that an IGP or static route is covering that prefix, I
remove the null route.... or not if you have several more specific routes.

On Fri, Dec 14, 2018 at 12:34 PM Mark Tinka <mark.tinka at seacom.mu> wrote:

>
>
> On 14/Dec/18 19:16, Joseph Mays wrote:
>
> >
> > The distribute lists shown also just contained appropriate permit and
> deny entries for 216.24.0.0 /18
>
> Firstly, please don't use distribute lists. This is very archaic and
> prone to mistakes. Suggest you migrate to prefix lists right away!
>
> >
> >
> > That changed the broadcast cogent was receiving, but not in the expected
> way. They only route they saw us broadcasting after that was the
> 216.24.60.0/23 route. Not the first one in the list, not the last one,
> not the biggest one or the smallest one, but just one route from the middle
> of the list. I don't get this behavior at all. Cogent cleared and bounced
> bgp to us, and still received only that one route in the broadcast from us.
>
> After you've fixed your filtering with prefix lists, you need to ensure
> that any "network..." statement is backed up by the presence of the very
> same route in your IGP (which includes static routing).
>
> Mark.
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