From owner-freebsd-questions@freebsd.org Tue Mar 9 20:53:22 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 C0E37570233 for ; Tue, 9 Mar 2021 20:53:22 +0000 (UTC) (envelope-from cyberleo@cyberleo.net) Received: from mail.cyberleo.net (paka.cyberleo.net [IPv6:2605:3e00::d8e2:80b4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4Dw6qk1F6wz3DtX for ; Tue, 9 Mar 2021 20:53:21 +0000 (UTC) (envelope-from cyberleo@cyberleo.net) Received: from [172.16.44.4] (vitani.den.cyberleo.net [216.80.73.130]) by mail.cyberleo.net (Postfix) with ESMTPSA id F02B3A2EFF; Tue, 9 Mar 2021 15:53:12 -0500 (EST) Subject: Re: IPv6 Startup To: Doug Hardie , FreeBSD Questions References: <3F059A72-F45B-43B1-8EE3-0176EE072054@sermon-archive.info> From: CyberLeo Kitsana Message-ID: <07f8c8b6-fb5c-6662-66de-8d5ecd0cc1fd@cyberleo.net> Date: Tue, 9 Mar 2021 14:53:11 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <3F059A72-F45B-43B1-8EE3-0176EE072054@sermon-archive.info> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 4Dw6qk1F6wz3DtX X-Spamd-Bar: --- Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=pass (policy=none) header.from=cyberleo.net; spf=pass (mx1.freebsd.org: domain of cyberleo@cyberleo.net designates 2605:3e00::d8e2:80b4 as permitted sender) smtp.mailfrom=cyberleo@cyberleo.net X-Spamd-Result: default: False [-3.80 / 15.00]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; FROM_HAS_DN(0.00)[]; RBL_DBL_DONT_QUERY_IPS(0.00)[2605:3e00::d8e2:80b4:from]; R_SPF_ALLOW(-0.20)[+mx]; NEURAL_HAM_LONG(-1.00)[-1.000]; MIME_GOOD(-0.10)[text/plain]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; SPAMHAUS_ZRD(0.00)[2605:3e00::d8e2:80b4:from:127.0.2.255]; TO_MATCH_ENVRCPT_SOME(0.00)[]; TO_DN_ALL(0.00)[]; NEURAL_HAM_SHORT(-1.00)[-1.000]; RCPT_COUNT_TWO(0.00)[2]; DMARC_POLICY_ALLOW(-0.50)[cyberleo.net,none]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:13706, ipnet:2605:3e00::/32, country:US]; RCVD_TLS_ALL(0.00)[]; MAILMAN_DEST(0.00)[freebsd-questions]; RCVD_COUNT_TWO(0.00)[2] 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: Tue, 09 Mar 2021 20:53:22 -0000 On 3/9/21 3:58 AM, Doug Hardie wrote: > I have two systems on the same ethernet. One is configured as a router, the other as a host. rtadvd is running on the router, rtsold on the host, and route6d on both. The router was up and running and I initiated tcpdump of ip6 packets on the interface. Then I booted the host. The results are interesting: > The question is, why are the host addresses being used before DAD is attempted? It appears there could be some really interesting problems if the link-layer address actually was duplicated. The problems would happen before DAD was even attempted? I would posit that this is because the fe80:: addresses used in the initial solicitation are derived from the MAC address of the interface, and if you have two interfaces with the same MAC address on the same subnet you have much bigger problems. -- Fuzzy love, -CyberLeo Technical Administrator CyberLeo.Net Webhosting http://www.CyberLeo.Net Element9 Communications http://www.Element9.net Furry Peace! - http://www.fur.com/peace/