[c-nsp] Redistribute interface address as a /32 or /128 into BGP

Saku Ytti saku at ytti.fi
Sat Mar 27 11:34:32 EDT 2021

On Sat, 27 Mar 2021 at 17:11, Maximilian Wilhelm <max at rfc2324.org> wrote:

> I'm wondering if the default classfulness is biting you here. Have you
> tried
>   network mask

His problem is that the connected network is less specific and he
wants to (potentially incorrect solution) advertise some addresses of
connected network as more-specific. So the problem is getting that /32
to RIB in the first place, the problem is not how to advertise after
he gets it to the RIB, which is what you're solving.

And solution to the question (probably not right solution) is to
static route /32 to the interface:

int eth42
ip route eth42

Now you can advertise This trick is particularly useful
so limit attack surface of your infrastructure, so instead of having
every PE-CE/31 address reachable, you can make it so that only CE/32
address is reachable, limiting DFZ wide surface.


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