From: Darren Ward (dward@xxxxxxxxxx)
Date: Sat Jun 02 2001 - 08:47:45 GMT-3
Yep, sorry I meant shorter that a /19 and not longer as everything actually
did say.
Somewhere in the work/study routing I must find some time to allocate to
sleep! :)
Darren
Bob Chahal wrote:
> No sure what you mean by better but if you want to filter /19 or longer
> prefixes from a neighbor
>
> then
>
> access-list 101 deny ip 0.0.0.0 255.255.255.255 255.255.224.0 0.0.31.255
> access-list 101 permit ip any any
>
> router bgp xx
> neighb y.y.y.y remote zz
> neighb distribute-list 101 in
>
> ----- Original Message -----
> From: "Darren Ward" <dward@pla.net.au>
> To: <ccielab@groupstudy.com>
> Sent: Saturday, June 02, 2001 11:16 AM
> Subject: BGP: Match prefixes gt using access-list?
>
> > Hi All,
> >
> > I've ben asked a damn good question by a co-worker and I must admit I'm
> > not exactly sure how to solve it.
> >
> > Q: Filter BGP advertisements to a neighbour so that only routes that are
> > /19 or better are advertised WITHOUT using a prefix-list.
> >
> > A:
> >
> > I know it will be a BGP extended IP access-list using the network/mask
> > pair but can't figure out the mask section properly.
> >
> > access-list 100 permit ip 0.0.0.0 255.255.224.0 255.255.224.0
> > 225.255.224.0
> >
> > Now, I _think_ this means match ANY network where the last 13 bits are
> > all zero AND the last 13 bits of the netmask are all zeros but allow
> > more zeros the base 13 bits (greater than /19)
> >
> > Is this correct?
> >
> > Darren Ward
> > (Sydney June 27-28)
> > **Please read:http://www.groupstudy.com/list/posting.html
**Please read:http://www.groupstudy.com/list/posting.html
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