Hi Joel, Announcing the /24 beside the /32s from each node isn't an option? Metric could be lowered too.
Rgds, Stefan Joel Brunenberg <[email protected]> schrieb am Fr., 17. Apr. 2015 00:22: > Hi Hans, Hi List, > > thank you for your clarification, > > On Thu, Apr 16, 2015 at 06:27:30PM +0200, Hans van Kranenburg wrote: > > Hi, > > > > On 16/04/15 16:43, Joel Brunenberg wrote: > > >[...] > > > > > >Another idea was a static route for the containing /24 that would be > > >exported via BGP while the /32 were filtered away. That however leaves > > >the /24 route in place even if there are no more /32 routes left. If > > >there is a way to change that, that would be great. > > > > Yes, I would suggest using a static blackhole route with the large > aggregate > > range for the BGP connection, and also export that to your local kernel > > routing table to automatically drop traffic for all addresses that are > > currently not in use. > > It seems I concentrated so much on the aspect of making the appearance > of the route conditional that I missed the obvious point. What you say > makes total sense. > > > Is there a special reason why you would want to have the /24 being > removed > > entirely if none of the other connections is up? > > I would like to retract the route in the case, no contributing routes > are there so traffic is no longer attracted in that case. If that is not > possible, a static blackhole route would be ok, too I guess. > > So its correct to assume that the following things would do? > > * in protocol static add a blackhole route for the aggregate network > * export the aggregate route to the kernel > * export the aggregate route to be BGP peers with next-hop self > * NO NOT export the aggreage to the OSPF areas > * Be happy and dance around the table > > I will have a try and see if it works. If there was a way to > conditionally import a specific protocol or filter on the presence of > specific prefixes in the RIB that would be awesome. > > Thank you so far, > > Joel > > /jbn > > -- > Joel Brunenberg - Troisdorf > PGP: 0xAD25981C >
