On Fri, 28 Jan 2005, Joe Maimon wrote:

I think these are two similar but very separate issues being talked about together, when maybe they shouldn't.

In the bogons case, I'd love to be able to take a bogon feed from a trusted source (i.e. team cymru) and have those routes put in the table as "special poison routes". I don't ever want another peer to be able to advertise any of those routes or more specifics, and if they do, I want to ignore those routes. The same logic could be applied to abusive networks you don't want to exchange traffic with.

The more general issue of ignoring more specifics for those who announce CIDRs and subnets of them for no obvious (or operational to me) reason is far more complicated as ideally you'd like the previously ignored more specifics to magically resurface if the aggregate route disappears.

If we treat these as separate issues/features, would it be that hard to have a route-map match statement in the very near future that could check incoming routes against a certain set of routes (perhaps by the next hop IP of the already installed routes) and reject them based on that?

i.e. Assume I have a feed of bogon routes and have their next-hop IP set to 192.0.2.1.

route-map blah-input deny 10 match existing-next-hop 192.0.2.1 route-map blah-input permit 20 ....

That doesn't seem like it'd be rocket science to implement...but then I've never seen cisco's BGP code.