Re: can't add a /24 blackhole route with a /32 loopback

Reply: Benoit Chesneau : "Re: can't add a /24 blackhole route with a /32 loopback"
In reply to: Benoit Chesneau : "can't add a /24 blackhole route with a /32 loopback"
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From: Alexander Chernikov <melifaro_at_FreeBSD.org>
Date: Wed, 14 Jun 2023 08:29:21 UTC


> On 14 Jun 2023, at 07:05, Benoit Chesneau <benoitc@enki-multimedia.eu> wrote:
> 
> Hi,
> 
> When I setup a loopback to a /32 , I can add a /24 as a blackhole route anymore. I can only create a /24 attached to this looopback. Ie.
Could you add a bit more context?
What is the FreeBSD version (uname -srm)?
What does 'route add 1.1.1.0/24 -blackhole’ show?
Could you also share netstat -4rnW and ifconfig output (maybe privately)?

> 
> when `lo1` is set to `1.1.1.1/32` I cant create a blackhole route to `1.1.1.0/24` using the command : ` route add 1.1.1.0/24 -blackhole` . Is there any reason for it? The idea is to be able to advertise the prefix `1.1.1.0/24` via BGP (bird) and use 1.1.1.1/32`  as a loopback distributed to other nodes using OSPF. I can probably make the loopback a /24  used by bird but what would be the other way to do it?
> 
> Benoît
>