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Date: Sat, 4 Dec 2021 17:22:47 +0100
From: Kurt Jaeger <pi@freebsd.org>
To: bz@freebsd.org
Cc: freebsd-net@freebsd.org
Subject: Re: why multi-hop icmp redirects to 0.0.0.0 on 13.0 ?
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Hi!

> > 10:20:16.889185 IP x.x.x..1 > y.y.y.1: ICMP redirect z.z.z.z to host 0.0.0.0, length 48
> 
> whoops.

> > This has been stopped by net.inet.ip.redirect=0 on rtr1, but my question is:
> > 
> > Why is rtr1 sending those multi-hop icmp redirects at all ?
> 
> Could you elaborate on:

> (a) Do rtr1 or rtr2 have a default route or are they carrying a full DFZ
>     without default route?

rtr1 runs frr, has full route, either with or without default route.

rtr2 has only static routes, default points to rtr1.

>     Assumption: if both rtr2 and rtr1 are running 13 and not 12, rtr2
>     does have a default route and rtr1 has a full DFZ only and no
>     default route?

Seeo above.

> (b) At the time this happens does rtr1 have a route to z.z.z.z ?
>     route -4 get z.z.z.z

Yes.

-- 
pi@FreeBSD.org         +49 171 3101372                  Now what ?