From nobody Sat Dec 04 16:19:41 2021 X-Original-To: freebsd-net@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id BC1AF18C0C5E for ; Sat, 4 Dec 2021 16:19:51 +0000 (UTC) (envelope-from bzeeb-lists@lists.zabbadoz.net) Received: from mx1.sbone.de (mx1.sbone.de [IPv6:2a01:4f8:13b:39f::9f:25]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mx1.sbone.de", Issuer "SBone.DE" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4J5vzW4B2pz4VQD; Sat, 4 Dec 2021 16:19:51 +0000 (UTC) (envelope-from bzeeb-lists@lists.zabbadoz.net) Received: from mail.sbone.de (mail.sbone.de [IPv6:fde9:577b:c1a9:31::2013:587]) (using TLSv1 with cipher ADH-CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by mx1.sbone.de (Postfix) with ESMTPS id 6F3518D4A129; Sat, 4 Dec 2021 16:19:44 +0000 (UTC) Received: from content-filter.sbone.de (content-filter.sbone.de [IPv6:fde9:577b:c1a9:31::2013:2742]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.sbone.de (Postfix) with ESMTPS id 96EA9E707AE; Sat, 4 Dec 2021 16:19:43 +0000 (UTC) X-Virus-Scanned: amavisd-new at sbone.de Received: from mail.sbone.de ([IPv6:fde9:577b:c1a9:31::2013:587]) by content-filter.sbone.de (content-filter.sbone.de [fde9:577b:c1a9:31::2013:2742]) (amavisd-new, port 10024) with ESMTP id on0FowJ7Ugk9; Sat, 4 Dec 2021 16:19:42 +0000 (UTC) Received: from nv.sbone.de (nv.sbone.de [IPv6:fde9:577b:c1a9:31::2013:138]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.sbone.de (Postfix) with ESMTPSA id 341E1E707AD; Sat, 4 Dec 2021 16:19:42 +0000 (UTC) Date: Sat, 4 Dec 2021 16:19:41 +0000 (UTC) From: "Bjoern A. Zeeb" To: Kurt Jaeger cc: freebsd-net@freebsd.org Subject: Re: why multi-hop icmp redirects to 0.0.0.0 on 13.0 ? In-Reply-To: Message-ID: References: X-OpenPGP-Key-Id: 0x14003F198FEFA3E77207EE8D2B58B8F83CCF1842 List-Id: Networking and TCP/IP with FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-net List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-net@freebsd.org MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Rspamd-Queue-Id: 4J5vzW4B2pz4VQD X-Spamd-Bar: ---- Authentication-Results: mx1.freebsd.org; none X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[] X-Spam: Yes X-ThisMailContainsUnwantedMimeParts: N 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