Date: Sat, 4 Dec 2021 16:19:41 +0000 (UTC) From: "Bjoern A. Zeeb" <bzeeb-lists@lists.zabbadoz.net> To: Kurt Jaeger <pi@freebsd.org> Cc: freebsd-net@freebsd.org Subject: Re: why multi-hop icmp redirects to 0.0.0.0 on 13.0 ? Message-ID: <alpine.BSF.2.00.2112041609520.68830@ai.fobar.qr> In-Reply-To: <Yast8d1dRd7ZFWr3@fc.opsec.eu> References: <Yast8d1dRd7ZFWr3@fc.opsec.eu>
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On Sat, 4 Dec 2021, Kurt Jaeger wrote:
> Hi!
>
> We (AS12502) recently upgraded one router from 12.2.x to 13.0.x. This
> caused some surprising effect, with the router sending out
> icmp redirects to 0.0.0.0 over multiple hops:
>
> Example:
>
> inet ------ wan:rtr1:lan ------ rtr2 ------ wan:host
> x.x.x.1 y.y.y.1
>
> host sends a packet to z.z.z.z and receives an icmp redirect from x.x.x.1
> like this:
>
> 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?
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?
(b) At the time this happens does rtr1 have a route to z.z.z.z ?
route -4 get z.z.z.z
/bz
--
Bjoern A. Zeeb r15:7
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