From: Daniel Ginsburg (dginsburg@mail.ru)
Date: Sat Jul 24 2004 - 16:10:45 GMT-3
On Sat, Jul 24, 2004 at 02:06:20PM -0400, James wrote:
> On Sat, Jul 24, 2004 at 10:49:26AM +0400, Daniel Ginsburg wrote:
> > On Thu, Jul 22, 2004 at 05:10:03PM -0400, James wrote:
> > > Also note that 'soft-reconfiguration inbound' is no longer
> > > necessary when you use routers that support Route Refresh
> > > capability (most routers today do. chances are your IOS
> > > version also does). With full internet routing table,
> > > 'soft-recon inbo' will waste a good chunk of RAM on your
> > > router for its usefulness that is already covered by
> > > route refresh.
> > >
> >
> > True. Route Refresh obviates need of 'soft-reconfiguration inbound' to
> > reconfigure BGP settings with dropping BGP session. But still
> > 'soft-reconfiguration inbound' is useful for debugging inbound filters. It
> > will let you see routes filtered by inbound filter, which is very useful
> > if you wonder where did you routes go.
>
> 'soft-recon in' will let you see the pure Adj-RIB-in before inbound policies
> are activated upon. So what you see in 'soft-reconfiguration inbound' is not
> what you see in 'sh ip bgp' when you have filters and policies.
>
> It is a good feature if you want to see what prefixes your peer is exactly
> sending you before you filter them off (for example, as you say, it will be
> a good troubleshooting tool to have it configured on some customer bgp
> sessions). However if you want to see what routes have been filtered (i.e.
> see what routes have been filtered by your inbound filter per neighbor
> basis), then there is no need for soft-recon, as you can simply type
> 'sh ip bgp neighbor a.b.c.d routes' to see the prefixes received from
> remote neighbor after your filtering and policies have been applied. :)
>
What I meant was simply that 'sh ip bg nei a.b.c.d received-routes'
needs 'soft-reconfiguration inbound' to be configured. 'sh ip bg nei
a.b.c.d rec' (unlike 'sh ip bg nei a.b.c.d routes') shows
routes _before_ filtering was applied which is useful to debug your
inbound filters and policies.
-- dg
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