From owner-freebsd-net@freebsd.org Sat Feb 20 23:02:14 2021 Return-Path: Delivered-To: freebsd-net@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 117B053AE5F for ; Sat, 20 Feb 2021 23:02:14 +0000 (UTC) (envelope-from bc979@lafn.org) Received: from mailman.nyi.freebsd.org (mailman.nyi.freebsd.org [IPv6:2610:1c1:1:606c::50:13]) by mx1.freebsd.org (Postfix) with ESMTP id 4DjkVF6Gfmz4qZj for ; Sat, 20 Feb 2021 23:02:13 +0000 (UTC) (envelope-from bc979@lafn.org) Received: by mailman.nyi.freebsd.org (Postfix) id D72A753B202; Sat, 20 Feb 2021 23:02:13 +0000 (UTC) Delivered-To: net@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id D6EDB53B14B for ; Sat, 20 Feb 2021 23:02:13 +0000 (UTC) (envelope-from bc979@lafn.org) Received: from mail.sermon-archive.info (sermon-archive.info [71.177.216.148]) by mx1.freebsd.org (Postfix) with ESMTP id 4DjkVD6h67z4qrv for ; Sat, 20 Feb 2021 23:02:12 +0000 (UTC) (envelope-from bc979@lafn.org) Received: from [10.0.1.251] (mini [10.0.1.251]) by mail.sermon-archive.info (Postfix) with ESMTPSA id 4DjkVC5Zzhz2fjQ4 for ; Sat, 20 Feb 2021 15:02:11 -0800 (PST) From: Doug Hardie Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.60.0.2.21\)) Subject: Re: IPv6 Fragmentation Date: Sat, 20 Feb 2021 15:02:11 -0800 References: <472A2B49-9BEC-4335-B6FB-AC4DAA0F0310@lurchi.franken.de> To: "net@freebsd.org" In-Reply-To: Message-Id: <5F0CE151-3B44-4692-AE82-F292B99BAC29@sermon-archive.info> X-Mailer: Apple Mail (2.3654.60.0.2.21) X-Virus-Scanned: clamav-milter 0.103.0 at mail X-Virus-Status: Clean X-Rspamd-Queue-Id: 4DjkVD6h67z4qrv X-Spamd-Bar: -- Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=pass (mx1.freebsd.org: domain of bc979@lafn.org designates 71.177.216.148 as permitted sender) smtp.mailfrom=bc979@lafn.org X-Spamd-Result: default: False [-2.70 / 15.00]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; FROM_HAS_DN(0.00)[]; RBL_DBL_DONT_QUERY_IPS(0.00)[71.177.216.148:from]; MV_CASE(0.50)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[multipart/alternative,text/plain]; PREVIOUSLY_DELIVERED(0.00)[net@freebsd.org]; DMARC_NA(0.00)[lafn.org: no valid DMARC record]; RCPT_COUNT_ONE(0.00)[1]; SPAMHAUS_ZRD(0.00)[71.177.216.148:from:127.0.2.255]; R_SPF_ALLOW(-0.20)[+ip4:71.177.216.148/32]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-1.00)[-0.998]; TO_DN_EQ_ADDR_ALL(0.00)[]; RCVD_NO_TLS_LAST(0.10)[]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+,1:+,2:~]; ASN(0.00)[asn:5650, ipnet:71.177.216.0/23, country:US]; RCVD_COUNT_TWO(0.00)[2]; MAILMAN_DEST(0.00)[net] Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.34 X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 20 Feb 2021 23:02:14 -0000 > On 20 February 2021, at 04:13, Kristof Provost wrote: >=20 > If you don=E2=80=99t have scrub fragment reassemble set then you have = to include something like pass log inet6 proto ipv6-frag all to pass = fragmented packets (assuming you block by default). >=20 > You really, really want scrub fragment reassemble because otherwise = your firewall can be trivially bypassed, but you need one of the two for = fragmented packets to work. >=20 I went with reassembly as it was easy to configure. However, is there = some place where the trivial bypassing is addressed in detail? I would = like to understand that. -- Doug