Filter based on BGP protocol status ...

[Alarig Le Lay]

On Thu 24 Mar 2022 07:43:03 GMT, Douglas Fischer wrote:
> I know that it is not the focus of your question, and also is not the focus
> on this mail list, but...
> 
> To that kind of automation, the best BGP engine you will find is ExaBGP. It
> is not focuses in been in compliance with all the concepts of a routing
> system itself. It's focus is exactly automations using API.
> 
> The scenario you described triggered-me something like a Zabbix looking to
> the status of BGP sessions of bird, and based on that doing API queries to
> a ExaBGP that is a iBGP peer of Bird.
> 
> This model is used on many tools focused in anomaly detection for
> triggering DDoS mitigation.
> 
> 
> But, if your intention is a much simpler scenario, the suggestion Maria
> made is the most common!
> You can used also some BGP communities(if your upstream supports it) for
> no-export for some prefixes... Sometimes it helps.

More simply, you can add a community on the non-ddos-protected provider
to make them lower the localpref to peer routes, and stop the prepend.

> Em qua., 23 de mar. de 2022 12:10, Xavier Trilla <xavier.trilla at clouding.io>
> escreveu:
> 
> > Hi,
> >
> >
> >
> > I’m quite sure this cannot be done, but I also know there is a lot of BIRD
> > I still don’t know, so here it goes:
> >
> >
> >
> > Is there any way to filter a export route based on another BGP session
> > status?
> >
> >
> >
> > For the sake of simplicity let’s say we have just two providers A and B,
> > and I only want to export some specific routes to B when A is down.
> >
> >
> >
> > I can do it externally with a quite simple script (For example: Check if
> > the provider is down via CLI and if it’s down insert the routes I want to
> > export to a kernel table and export that to provider B) but it would be
> > nice if I could do it directly in Bird.
> >
> >
> >
> > I’ve been scratching my head around this, but unless there is something
> > like if proto.A == down on the filters I don’t really see how to do it (Or
> > maybe some way to raise a global flag based on if I’m receiving routes via
> > provider B, but I don’t think that can’t be done either.)
> >
> >
> >
> > Thanks for your time!
> >
> > Xavier
> >
> >
> >