Review my BGP configuration

[Andre Nathan]

On Fri, 08 Mar 2013, Hans van Kranenburg wrote:

> When converting the other router to bird, you can also configure it to
> just use the /24 ranges in the context of talking to the ebgp peer, and
> never let them come near the t_bgp or even master table, so you don't
> need the additional filters to keep them out again.

Borrowing your routing table scheme from your first reply:

    +--------+
    | master |
    +--------+
       ^ |
       | |  p_bgp_to_master
       | v
    +--------+  --->
    | t_bgp  |  <--- iBGP
    +--------+
       ^ |
       | |  p_wzyx_to_bgp
       | v
    +--------+  --->
    | t_wzyx |  <--- eBGP to wzyx
    +--------+
       ^
       |  originate_to_wzyx
       |
    bgp routes we
    want to announce

In the eBGP session I have an input filter that rejects routes matching
my /24. What happens here is that despite the filter, those routes
still end up being added to t_bgp because they were added to t_wzyx via
originate_to_wzyx. Is that correct?

If so, the solution is see is to change p_wzyx_to_bgp so that instead of
'import where proto = "eBGP"' a more complex filter is used, something
like

  if proto = "eBGP" && ! (net ~ [a.b.0.0/24, a.b.1.0/24]) then {
    accept;
  }
  reject;

Looks good?

> Why would a route with target 'reject' not be added to the kernel table
> if you export the route to it?

Please ignore that, it was a brain malfunction.

Thank you,
Andre
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