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

Hi,

Thanks for your answer. I'm using Freebsd 13.2 latest version:

$ uname -srm
FreeBSD 13.2-RELEASE amd64

I edited the filtred result of the table since it has a full view:

netstat -4rnW |grep -e "1.1.1"
1.1.1.0/24    127.0.0.1          USB        14  16384        lo0
1.1.1.1       link#9             UHS        26  16384        lo1
1.1.1.2       10.3.1.1           UGH1       15   9000   vlan2212
1.1.1.2       10.3.1.1           UGHS       16   1500   vlan2212
1.1.1.2       10.3.1.1           UGHS       25   9000   vlan2212


Also I forgot to mention that the ethernet driver is MLX4EN(4):

mlx4_core0@pci0:8:0:0:	class=0x028000 rev=0x00 hdr=0x00 vendor=0x15b3 device=0x1007 subvendor=0x103c subdevice=0x22f3
    vendor     = 'Mellanox Technologies'
    device     = 'MT27520 Family [ConnectX-3 Pro]'
    class      = network
     Corrected = Advisory Non-Fatal Error



Hope it helps,


Benoît 
------- Original Message -------
On Wednesday, June 14th, 2023 at 10:29, Alexander Chernikov <melifaro@FreeBSD.org> wrote:


> > 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