From nobody Wed Apr 2 00:47:19 2025 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 4ZS5nD5FNMz5sMvK for ; Wed, 02 Apr 2025 00:47:44 +0000 (UTC) (envelope-from jamie@catflap.org) Received: from donotpassgo.dyslexicfish.net (donotpassgo.dyslexicfish.net [IPv6:2001:19f0:7400:8808:12:4:0:1]) by mx1.freebsd.org (Postfix) with ESMTP id 4ZS5nC5gDWz3XFN for ; Wed, 02 Apr 2025 00:47:43 +0000 (UTC) (envelope-from jamie@catflap.org) Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=pass (policy=none) header.from=catflap.org; spf=pass (mx1.freebsd.org: domain of jamie@catflap.org designates 2001:19f0:7400:8808:12:4:0:1 as permitted sender) smtp.mailfrom=jamie@catflap.org X-Catflap-Envelope-From: X-Catflap-Envelope-To: freebsd-net@FreeBSD.org Received: from donotpassgo.dyslexicfish.net (donotpassgo.dyslexicfish.net [209.250.224.51]) by donotpassgo.dyslexicfish.net (8.14.5/8.14.5) with ESMTP id 5320lKqL093324; Wed, 2 Apr 2025 01:47:20 +0100 (BST) (envelope-from jamie@donotpassgo.dyslexicfish.net) Received: (from jamie@localhost) by donotpassgo.dyslexicfish.net (8.14.5/8.14.5/Submit) id 5320lJaL093323; Wed, 2 Apr 2025 01:47:19 +0100 (BST) (envelope-from jamie) From: Jamie Landeg-Jones Message-Id: <202504020047.5320lJaL093323@donotpassgo.dyslexicfish.net> Date: Wed, 02 Apr 2025 01:47:19 +0100 Organization: Dyslexic Fish To: freebsd-net@FreeBSD.org, cross+freebsd@distal.com Subject: Re: RFC4941 IPv6 privacy knobs and how to set them References: In-Reply-To: User-Agent: Heirloom mailx 12.4 7/29/08 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=utf-8 Content-Transfer-Encoding: 8bit X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.2.7 (donotpassgo.dyslexicfish.net [209.250.224.51]); Wed, 02 Apr 2025 01:47:20 +0100 (BST) X-Spamd-Result: default: False [-1.96 / 15.00]; NEURAL_HAM_MEDIUM(-0.83)[-0.825]; NEURAL_HAM_SHORT(-0.80)[-0.803]; DMARC_POLICY_ALLOW(-0.50)[catflap.org,none]; NEURAL_SPAM_LONG(0.37)[0.371]; R_SPF_ALLOW(-0.20)[+mx:dyslexicfish.net]; MIME_GOOD(-0.10)[text/plain]; RCVD_NO_TLS_LAST(0.10)[]; TO_DN_NONE(0.00)[]; ASN(0.00)[asn:20473, ipnet:2001:19f0:7400::/38, country:US]; ARC_NA(0.00)[]; HAS_ORG_HEADER(0.00)[]; MIME_TRACE(0.00)[0:+]; FREEFALL_USER(0.00)[jamie]; TO_MATCH_ENVRCPT_SOME(0.00)[]; FROM_HAS_DN(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; MLMMJ_DEST(0.00)[freebsd-net@FreeBSD.org]; TAGGED_RCPT(0.00)[freebsd]; R_DKIM_NA(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; RCPT_COUNT_TWO(0.00)[2] X-Rspamd-Queue-Id: 4ZS5nC5gDWz3XFN X-Spamd-Bar: - Chris Ross wrote: > Is there documentation about what these variables mean, and if “2” is > a useful value different than “1”? If so, how are they different? Hi, Chris. From: /usr/share/doc/IPv6/IMPLEMENTATION : | As documented in the source address selection document, temporary | addresses for privacy extension are less preferred to public addresses | by default. However, for administrators who are particularly aware of | the privacy, there is a system-wide sysctl(3) variable | "net.inet6.ip6.prefer_tempaddr". When the variable is set to | non-zero, the kernel will rather prefer temporary addresses. The | default value of this variable is 0. Additionally, the files in /usr/src/sys/netinet6/ treat the value as a boolean, so it appears that in this case, 2 isn't twice as private as 1 :-) Cheers, Jamie