Re: prefix advertisement in bpg

so far i did not see any logical reason to point it to null 0 ,

 in case servers are using private ip, and they do nat to translate public
block to private block . but since this public subnet is non existant we
need a route for nat to work,

is my mind correct ?

On Mon, Apr 15, 2013 at 9:40 AM, David Rothera <david.rothera_at_gmail.com>wrote:

> It doesn't have to be in an IGP (unless you are using IGP sync) but simply
> the routing table itself, either by a static route or from an IGP.
>
> Regards
>
> David Rothera
> CCIE #38338
> Sent from my iPhone
> Please excuse any mistakes and brevity.
>
> On 15 Apr 2013, at 06:14, Ahmed Hussain <engine10_at_gmail.com> wrote:
>
> > Before BGP can advertise the prefix it has to be in IGP. thats what the
> > null route is doing.
> >
> >
> > On Fri, Apr 12, 2013 at 10:01 PM, Imran Ali <immrccie_at_gmail.com> wrote:
> >
> >> why some bgp implementations adds a null route for advertised
> prefixes
> >>
> >> ex
> >>
> >> router bgp 2
> >> bgp log-neighbor-changes
> >> network 128.16.16.0 mask 255.255.255.0
> >> network 130.130.0.0
> >> neighbor 10.10.10.1 remote-as 1 * neighbor 10.10.10.1 advertise-map
> >> ADVERTISE non-exist-map NON-EXIST***neighbor 10.10.20.3 remote-as 3
> >> !
> >> ip route 130.130.0.0 255.255.0.0 *Null0*
> >>
> >>
> >>
> >> is has something to do with NAT ?
> >>
> >>
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Received on Mon Apr 15 2013 - 10:16:03 ART