BGP community not being set on outbound BGP updates

[Lex van Roon]

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Hi All,

I'm building a s/RTBH setup based on bird 1.3.7. I'm using a single
route injector which has iBGP peerings with my route-reflector cluster.
The setup looks like this (with the injector running on
OpenBSD-4.9/Alpha and router* running on Debian Squeeze amd64 if that
matters):

      [injector]
      /       \
     /         \
    /           \
[router 1]   [router 2]

On the injector, I configure static routes, which I export over BGP. I
want to tag these prefixes with a BGP community, so I can nullroute the
IP's on my route-reflectors and all routers that are connected to this
cluster.

For this, I'm using the following configuration (only the relevant
portions included):

[injector]
protocol static blacklist {
        route 1.2.3.4/32 via 192.0.2.1;
}

protocol bgp router_1 {
        local 172.16.0.1 as 65000;
        neighbor 172.16.0.2 as 65000;
        export filter {
                bgp_community = -empty-;
                bgp_community.add((65000,666));
                accept;
        };
        import none;
}

[router 1]
protocol bgp injector {
        local 172.16.0.2 as 65000;
        neighbor 172.16.0.1 as 65000;
        export none;
        import filter {
                gw = 192.0.2.1;
                bgp_community = -empty-;
		bgp_community.add((65000,666));
                accept;
        };
}

The configuration for router 2 is identical apart from the IP's, so I
haven't included this configuration. This setup works, however, the BGP
community only gets set when the prefix enters BGP on router 1:

user at injector# birdc show route 1.2.3.4/32 all
BIRD 1.3.7 ready.
1.2.3.4/32  via 192.0.2.1 on lo1 [blacklist 12:01] * (200)
        Type: static unicast univ
user at injector# birdc show route export router_1 all
BIRD 1.3.7 ready.
1.2.3.4/32  via 192.0.2.1 on lo1 [blacklist 12:01] * (200)
        Type: static unicast univ
        BGP.origin: IGP
        BGP.as_path:
        BGP.next_hop: 192.0.2.1
        BGP.local_pref: 100

user at router_1# birdc show route 1.2.3.4/32
BIRD 1.3.7 ready.
1.2.3.4/32  unreachable [injector 12:01 from 172.16.0.1] * (100) [i]
user at router_1# birdc show route 1.2.3.4/32 all
BIRD 1.3.7 ready.
1.2.3.4/32  unreachable [injector 12:01 from 172.16.0.1] * (100) [i]
	Type: BGP unicast univ
	BGP.origin: IGP
	BGP.as_path:
	BGP.next_hop: 192.0.2.1
	BGP.local_pref: 100
	BGP.community: (65000,666)

My questions:

1) First, are these configuration snippets and command output enough to
assist in these questions?
2) Is it possible to set a BGP community on a static route which is
being exported over BGP? The example in the docs(*) says I should be
able to do this.
3) Am i doing something wrong in this setup that is causing the BGP
community not being set?
4) Is there a more intelligent way to get this to work? Imho, using a
BGP community is the most cleanest and generic way to implement this,
but I want this to be set on the injector, and not on my RR cluster.

Kind Regards,

Lex van Roon

*) http://bird.network.cz/?get_doc&f=bird-6.html#ss6.1

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