Filter route attribute "from"

[Ondrej Zajicek]

On Wed, Nov 11, 2020 at 03:44:48PM +0200, Alex Rydzewski wrote:
> Good times, bird community!
> 
> I'm have trouble with filter routes by "from" attribute.
> 
> Routes in Bird route table have data about router which the route has
> originated from:
> 80.239.201.11/32   via 193.124.176.1 on eth1 [kernel1 2020-08-11] * (10)
> 10.0.0.0/30        via 10.0.0.18 on bond0 [MyOSPF 2020-11-09] * I (150/20)
> [172.21.1.1]
> 154.47.36.2/32     via 193.124.176.1 on eth1 [kernel1 2020-08-13] * (10)
> 
> but if i try get that routes:
> show route where from = 172.21.1.1
> 
> I get empty respond without any errors.
> ...
> Explain me please, what i understand wrong about that?


Hello

OSPF routes do not have meaningful 'from' attribute. This attribute
describes a neighboring router from which we received such route. It
makes sense for BGP, RIP and other vector/path distance routing
protocols.  OSPF protocol (and other link-state routing protocols) does
not exchange routes, instead exchange network topology and compute routes
locally, so these routes does not have valid 'from' attribute.

What you see in '[172.21.1.1]' is not from, but ospf_router_id attribute,
describing router id of a router originating that route.

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
"To err is human -- to blame it on a computer is even more so."