On Wed, Mar 25, 2015 at 01:49:31AM +0000, Michael Graham wrote: > Hi all, > > I've been trying to understand what I should do about my current IPv6 > wows. > > I have an IPv6 enabled network but when on a clean boot I don't get an > IPv6 address (in Jessie BTW), I've tracked this down to this message in > dmeg: > > IPv6: wlan0: IPv6 duplicate address fe80::fef8:aeff:fe7b:115f detected! This is the link-local address for the device with a MAC address of FC:F8:AE:xx:xx:7B:11:5F (where xx:xx is obscured by the IP address). Duplicate Address Detection works by the interface joining a multicast address and sending a Neighbour Solicitation message (similar to ARP's "Who has this address?" message). If the interface either gets a Neighbour Advertisement reply, or sees a Neighbour Solicitation message with the address it wants, then that implies that some other interface on the network wants that address and there is a clash. So, perhaps the DAD is correct and there is another device on your network trying for the same address (note that the address space of autoconfigured link-local addresses is smaller than that of MAC addresses - due to the FF:FE in the middle - so there IS a slim chance of a valid collision). Another alternative is a network issue - a routing loop or something - causing the interface to see its own NS message. I would suggest using wireshark or similar to listen for ICMPv6 messages and see what happens when the interface comes up. > > And can now get an IPv6 address on my laptop by disabling doing: > > echo 0 | sudo tee /proc/sys/net/ipv6/conf/*/accept_dad If you're happy that you're NOT actually going to get duplicate addresses on your network, then disabling DAD might be an acceptable option. > > However, I don't know what to do next... this seems like a bug. But I > have no idea what package is should raise it against? Is it ifconfig, > networkmanager, linux, systemd?
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