OSPF protocol and export filters for E2 routes

[Ondrej Zajicek]

On Wed, Dec 09, 2020 at 05:48:18PM +0000, Nigel Kukard wrote:
> Hi guys,
> 
> I'm wondering if someone knows the answer to this, here is the setup...
> 
> 
> What I am seeing is this works 100% as expected in RIP.
> 
> When I try the same thing with OSPF, I am not seeing it being rejected
> on R2. Infact, I am not seeing the E2 route at all pass through the
> export filter. But I am receiving it on R3.
> 
> I just want to make sure this is expected or unexpected behavior?

Hi

It is expected behavior. There is a fundamental difference between
vector/path distance routing protocols (RIP, BGP) and link-state routing
protocols (OSPF, IS-IS). The former pass around routes (and can decide
what is passed in each step), the later pass around network topology
description and can control propagation only on boundaries (like
between OSPF areas).

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
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"To err is human -- to blame it on a computer is even more so."