Inject BGP routes with non directly-connected next-hop

[dave seddon]

That's the difference between iBGP and eBGP:

https://tools.ietf.org/html/rfc4271#section-5.1.3

On Tue, Apr 7, 2015 at 5:39 AM, Jan Huňka <jan.hunka at gmail.com> wrote:

> Hello,
>
> I'm currently trying to configure BIRD for BGP injection. Routes which are
> added on BIRD should be distributed to specified neighbor router (in this
> case Cisco) and added to it's routing table. I also need to specify
> next-hop IP address of these routes, because injected routes should divert
> the matching traffic through another way until BIRDS stops to distribute
> these routes.
>
> I was able to configure BIRD to inject these routes with specified
> next-hop using internal BGP. But I also need it to work with external BGP.
> The problem is that the next-hop IP of injected routes is a directly
> connected network of the Cisco router and not BIRD's. BIRD doesn't know
> anything about this network. So the question is, is it possible to inject
> routes from BIRD to Cisco router using external BGP with next-hop IP
> address, which is not directly connected to the BIRD router?
>
> I should add that the BGP injection using external BGP works too, but only
> If the next-hop IP is a directly connected network od the BIRD router.
>
> Thank you for any advice.
>
> Jan Huňka
>
>
> Configuration of BIRD:
>
> protocol device {
>         scan time 10;
> }
>
> protocol static static_10 {
>         route 5.100.100.0/24 reject;
> }
>
> # filters section (DO NOT REMOVE!)
> filter filter_10 {
> if ( proto = "static_10" ) then {
> bgp_community.add((25511,444));
> bgp_next_hop=3.100.100.1;
> accept;
> } else {
>  reject;
> }
> }
>
> protocol bgp bgp_10 {
> local as 25511;
> neighbor Y.Y.Y.Y as 25512;
> import all;
> export filter filter_10;
> }
>
> Configuration of the bgp process on the CISCO router:
>
> router bgp 25512
>  neighbor X.X.X.X remote-as 25511
> !
> address-family ipv4
>   neighbor X.X.X.X activate
>   no auto-summary
> !
>
>
>
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