From owner-freebsd-net@FreeBSD.ORG Sun Jun 12 22:30:47 2011 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 4A848106564A for ; Sun, 12 Jun 2011 22:30:47 +0000 (UTC) (envelope-from spork@bway.net) Received: from xena.bway.net (xena.bway.net [216.220.96.26]) by mx1.freebsd.org (Postfix) with ESMTP id 172558FC08 for ; Sun, 12 Jun 2011 22:30:46 +0000 (UTC) Received: (qmail 28023 invoked by uid 0); 12 Jun 2011 22:30:44 -0000 Received: from smtp.bway.net (216.220.96.25) by xena.bway.net with (DHE-RSA-AES256-SHA encrypted) SMTP; 12 Jun 2011 22:30:44 -0000 Received: (qmail 28019 invoked by uid 90); 12 Jun 2011 22:30:44 -0000 Received: from unknown (HELO hotlap.nat.fasttrackmonkey.com) (spork@96.57.144.66) by smtp.bway.net with (DHE-RSA-AES256-SHA encrypted) SMTP; 12 Jun 2011 22:30:44 -0000 Date: Sun, 12 Jun 2011 18:30:44 -0400 (EDT) From: Charles Sprickman X-X-Sender: spork@hotlap.nat.fasttrackmonkey.com To: freebsd-net@freebsd.org Message-ID: User-Agent: Alpine 2.00 (OSX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII Subject: link-local needed w/static IP and gateway? X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 12 Jun 2011 22:30:47 -0000 Hello, I've been trying to wrap my head around the differences between address resolution in IPv6 and IPv4 and I'm a bit confused by a real-world issue I'm seeing in a colo facility where we have dual-stack connectivity. Basically, what I see is summed up in this recent post: http://freebsd.1045724.n5.nabble.com/Proper-way-to-setup-IPv6-gateway-on-running-node-without-reboot-td4313847.html If I manually configure a static IPv6 IP and then set a default route for a router on the same subnet, ie: ifconfig em0 inet6 2001:xxx:xxxx::2/48 route add -inet6 default 2001:xxx:xxxx::1 I have no issues pinging other hosts on the subnet (which also have static IPs and manually configured gateways), but I find that address resolution for the router is spotty at best. If I start and maintain a ping from the host to the router, the first few packets are lost, then traffic flows. If I'm pinging from an outside host, once I stop the ping from the host to the gateway, the external ping fails shortly thereafter. I can also get traffic to flow to the gateway briefly by running "rtsol em0", but after a few minutes it stops. Now following the steps in the thread linked above works, and what that basically has you do is enable link-local addresses, down/up the interface, and then all is well. Can anyone help me understand what the relationship is between address resolution for the router and link-local? Why is this required? Why can I ping other hosts on the subnet without enabling link-local? I understand link-local is needed for *automatic* router discovery, but in my case I'm explicity setting a default route. I'm having a hard time finding good docs on this, most tutorials seem to center around a tunneling setup or simple autoconfigured LAN stuff - no one's really addressing typical colo/datacenter configs. I've got my workaround, but I'd like to understand what's going on. Thanks, Charles