From owner-freebsd-questions@freebsd.org Mon May 3 00:40:34 2021 Return-Path: Delivered-To: freebsd-questions@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 13294621AF4 for ; Mon, 3 May 2021 00:40:34 +0000 (UTC) (envelope-from bc979@lafn.org) Received: from mail.sermon-archive.info (sermon-archive.info [47.181.130.121]) by mx1.freebsd.org (Postfix) with ESMTP id 4FYPJw6hJkz3m35 for ; Mon, 3 May 2021 00:40:32 +0000 (UTC) (envelope-from bc979@lafn.org) Received: from smtpclient.apple (mini [10.0.1.251]) by mail.sermon-archive.info (Postfix) with ESMTPSA id 4FYPJp4zVDz2fjPy; Sun, 2 May 2021 17:40:26 -0700 (PDT) From: Doug Hardie Message-Id: Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.80.0.2.43\)) Subject: Re: PF with IPv6 Date: Sun, 2 May 2021 17:40:26 -0700 In-Reply-To: <90DCF979-C3AE-4775-BE39-DB3F455F7D4E@gromit.dlib.vt.edu> Cc: FreeBSD Questions To: Paul Mather References: <90DCF979-C3AE-4775-BE39-DB3F455F7D4E@gromit.dlib.vt.edu> X-Mailer: Apple Mail (2.3654.80.0.2.43) X-Virus-Scanned: clamav-milter 0.103.1 at mail X-Virus-Status: Clean X-Rspamd-Queue-Id: 4FYPJw6hJkz3m35 X-Spamd-Bar: / Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=pass (mx1.freebsd.org: domain of bc979@lafn.org designates 47.181.130.121 as permitted sender) smtp.mailfrom=bc979@lafn.org X-Spamd-Result: default: False [-0.61 / 15.00]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-0.91)[-0.908]; FROM_HAS_DN(0.00)[]; RBL_DBL_DONT_QUERY_IPS(0.00)[47.181.130.121:from]; MV_CASE(0.50)[]; R_SPF_ALLOW(-0.20)[+mx]; MIME_GOOD(-0.10)[multipart/alternative,text/plain]; DMARC_NA(0.00)[lafn.org: no valid DMARC record]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_SPAM_SHORT(1.00)[0.999]; SPAMHAUS_ZRD(0.00)[47.181.130.121:from:127.0.2.255]; TO_MATCH_ENVRCPT_SOME(0.00)[]; TO_DN_ALL(0.00)[]; RCPT_COUNT_TWO(0.00)[2]; 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:47.181.128.0/18, country:US]; RCVD_COUNT_TWO(0.00)[2]; MAILMAN_DEST(0.00)[freebsd-questions] Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.34 X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 03 May 2021 00:40:34 -0000 > On 1 May 2021, at 07:37, Paul Mather wrote: >=20 > On Fri, 30 Apr 2021 21:20:48 -0700, Doug Hardie > wrote: >=20 >> Message: 3 >> Date: Fri, 30 Apr 2021 21:20:48 -0700 >> From: Doug Hardie > >> To: FreeBSD Questions > >> Subject: PF with IPv6 >> Message-ID: <2CD4806C-F1A4-4DDE-8C2F-2B0A08EA2A18@sermon-archive.info = > >> Content-Type: text/plain; charset=3Dus-ascii >>=20 >> FreeBSD 13-RELEASE. I have a small test network setup and tried to = block all IPv6 except those addressed to a specific address. = /etc/pf.conf contained: >>=20 >> ext_if =3D "bge0" >> LAN3 =3D "2001:1000:0:3000::/64" >> pass in quick log on $ext_if proto ipv6 from $LAN3 to $LAN3 >> block in log on $ext_if proto ipv6 from any to any >>=20 >> Nothing got blocked. pftop showed all zeros for both rules. I then = added at the end: >>=20 >> pass in quick log on $ext_if proto icmp6 from $LAN3 to $LAN3 >> block in log on $ext_if proto icmp6 from any to any >>=20 >> A lot of stuff got blocked. The log shows many entries like: >>=20 >> 15:59:41.597632 rule 3/0(match): block in on bge0: (hlim 1, = next-header Options (0) payload length: 32) fe80::120c:6bff:fe5d:4404 > = ff02::1: HBH (rtalert: 0x0000) (pad1)(pad1) ICMP6, multicast listener = query >> 0x0000: 6000 0000 0020 0001 fe80 0000 0000 0000 = `............... >> 0x0010: 120c 6bff fe5d 4404 ff02 0000 0000 0000 = ..k..]D......... >> 0x0020: 0000 0000 0000 0001 3a00 0502 0000 0000 = ........:....... >> 0x0030: 8200 98aa .... >>=20 >> Rule 3 is the block for ICMP6, but those are clearly IP6 packets that = should have been blocked by rule 1. Is there a problem with IPv6 and pf? >=20 >=20 > It's not clear to me precisely what you are trying to achieve. The = "proto" keyword in PF rules refers to protocols in /etc/protocols. Your = rules appear to be targeting the specific case of filtering IPv6 = encapsulated in IPv4. I don't believe that is what you intend. >=20 > The more standard way in PF to block IPv6 vs IPv4 traffic is to use = "inet" (IPv4) or "inet6" (IPv6) to target IPv4 or IPv6 packets. >=20 > Note, the last rule you added that you say did start blocking things = is more typical of rules to block ICMP6. Because you omit "inet" or = "inet6" on the rule it will be applied to both IPv4 and IPv6 packets. = But, the "proto icmp6" part is specifically targeting ICMP6. >=20 > So, to summarise, use "inet" and "inet6" to select IPv4 and IPv6 and = "proto" to select the protocol you want to target (e.g., "tcp", "udp", = "icmp", "icmp6", etc.). E.g., "pass in log quick on $ext_if inet6 from = ..." to allow all IPv6 for the rule, or ""pass in log quick on $ext_if = inet6 proto tcp from ..." to allow only IPv6 TCP traffic, etc. First, it appeared to me that since ipv6 is listed in /etc/protocols, = that it could be used as a protocol. However, after reading the man = page again, I see where it wants family, not protocol. With that change = it does work. What I was trying to do was to simulate a multi LAN configuration using = only one physical LAN. This is quite easy to do with IPv4, but even = with a bunch of pf rules, there are issues with the multicast packets. = Hosts should only listen to packets addressed to their virtual LAN but = multicast packets are not identifiable by which virtual LAN they were = sent to. So I ended up adding a bunch of switches and building the = complete multi LAN configuration. Thanks, --Doug