BGP communities

[Fabiano D'Agostino]

This is the bird.conf of the route server:
https://pastebin.com/qwp6nBtz
This is the bird.conf of one router:
https://pastebin.com/trwgKG92

Why does AS3 still receive routes from AS2? What am I missing?

Thanks,

Il giorno lun 6 apr 2020 alle ore 18:13 Alexander Zubkov <green at qrator.net>
ha scritto:

> It is really hard to guess what routes you have actually in your
> bird's table and how your bird is configured.
>
> > I just edited the bird.conf of the route server, should I also edit the
> bird.conf of the routers which are peering with the route server?
>
> Filters on peers can affect only communities you are sending and other
> attributes, but they do not affect directly the logic of your route
> server's filters, there is no magic here.
>
> On Mon, Apr 6, 2020 at 6:08 PM Fabiano D'Agostino
> <fabiano.dagostino96 at gmail.com> wrote:
> >
> > Does 'show route where' exist as command? Because I have syntax error.
> > Anyway I set up my route server as here:
> > https://www.slideshare.net/apnic/bird-routing-daemon
> > But I am having the problem described here:
> > https://bird.network.cz/pipermail/bird-users/2010-September/001620.html
> >
> > I just edited the bird.conf of the route server, should I also edit the
> bird.conf of the routers which are peering with the route server?
> >
> > Thanks,
> >
> > Il giorno lun 6 apr 2020 alle ore 17:50 Alexander Zubkov <
> green at qrator.net> ha scritto:
> >>
> >> Have you tried to check that in cli like:
> >> show route where bgp_out(...)
> >> And check that required route has all needed communities:
> >> show route all x.x.x.x/y
> >>
> >> On Mon, Apr 6, 2020 at 5:35 PM Fabiano D'Agostino
> >> <fabiano.dagostino96 at gmail.com> wrote:
> >> >
> >> > Hey,
> >> > thank you! I think I am having the same problem they had here:
> >> >
> https://bird.network.cz/pipermail/bird-users/2010-September/001620.html
> >> >
> >> > But I didn't understand how they solved.
> >> >
> >> > Regards,
> >> > Fabiano
> >> >
> >> > Il giorno lun 6 apr 2020 alle ore 17:16 Cybertinus <
> bird at cybertinus.nl> ha scritto:
> >> >>
> >> >> Hello Fabiano,
> >> >>
> >> >>
> >> >> BGP Communities are basically tags you add to a prefix that is
> received from, or send to, a peer. And in Bird you can do whatever you want
> with these communities. A community by itself has no meaning and has no
> influence on the routing decision whatsoever. It is the meaning you add to
> it in your configuration what makes them work.
> >> >>
> >> >> More information about communities:
> https://en.wikipedia.org/wiki/Border_Gateway_Protocol#Communities
> >> >>
> >> >>
> >> >> Kind regards,
> >> >> Cybertinus
> >> >>
> >> >>
> >> >> On 2020-04-06 17:03, Fabiano D'Agostino wrote:
> >> >>
> >> >> and how these kind of checks are handled?
> >> >> if (myas,peeras) ~ bgp_community  what is bgp_community?
> >> >>
> >> >> Thanks,
> >> >>
> >> >> Il giorno lun 6 apr 2020 alle ore 15:32 Fabiano D'Agostino <
> fabiano.dagostino96 at gmail.com> ha scritto:
> >> >>
> >> >> Thank you, but "if the route does not come from BGP then false"
> >> >> here I have:
> >> >> protocol pipe a {
> >> >>     table master;
> >> >>     mode transparent;
> >> >>     peer table a;
> >> >>     import all;
> >> >>     export where bgp_out(x); => this becomes false, what does this
> mean?
> >> >>     #export all;
> >> >> }
> >> >>
> >> >> Thanks,
> >> >>
> >> >> Il giorno lun 6 apr 2020 alle ore 10:50 Bernd Naumann <
> bena at spreadshirt.net> ha scritto:
> >> >>
> >> >> On 05.04.20 23:08, Fabiano D'Agostino wrote:
> >> >> > Good evening,
> >> >> > could someone explain me the meaning of these lines?
> >> >> >
> >> >> > function bgp_out(int peeras)
> >> >> > {
> >> >> > if ! (source = RTS_BGP ) then return false;
> >> >> > if peeras > 65535 then return true; ### communities do not support
> AS32
> >> >> > if (0,peeras) ~ bgp_community then return false;
> >> >> > if (myas,peeras) ~ bgp_community then return true;
> >> >> > if (0, myas) ~ bgp_community then return false;
> >> >> > return true;
> >> >> > }
> >> >> >
> >> >> > Thanks,
> >> >> >
> >> >> > Fabiano
> >> >> >
> >> >>
> >> >> Morning,
> >> >>
> >> >> I can not cover the whole section but as a start...
> >> >>
> >> >> * if the route does not come from BGP then false (routing table
> source?)
> >> >> * if the remote AS Number is greater 65535 (16 Bit) then "just"
> return
> >> >> true (see AS 32 Bit Numbers, and the non-support of older
> >> >> devices/implementations)
> >> >> * For the next 3 I'm not 100% sure how to read but I found
> >> >>
> https://bird-users.network.narkive.com/3uDbo6H9/any-ix-willing-to-share-their-config
> >> >>
> >> >> ```
> >> >> 0:XXXXX - Do not announce route to peer XXXXX
> >> >> 0:MyASN - Do not announce route to all peers
> >> >> MyASN:XXXXX - Announce route to peer XXXXX only
> >> >> MyASN:MyASN - Announce routes to all peers. This community is
> >> >> automatically added to all routes that are not
> >> >> tagged with any of MyASN:XXXXX communities.
> >> >> ```
> >> >>
> >> >> Maybe this helps a little bit.
> >> >>
> >> >> Bernd
>
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