Date: Sun, 12 Jun 2011 18:30:44 -0400 (EDT) From: Charles Sprickman <spork@bway.net> To: freebsd-net@freebsd.org Subject: link-local needed w/static IP and gateway? Message-ID: <alpine.OSX.2.00.1106121814540.99056@hotlap.nat.fasttrackmonkey.com>
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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
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