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I recently discovered that my ISP supports IPv6 so I decided to give it a spin, configured the router, tried pinging ipv6.google.com from the router, all fine. I configure RADVD for the internal network (5 macs) and all of them happily pick up IPv6 addresses. I check connectivity with http://test-ipv6.com and all works well except one machine.

It has an IPv6 address, but it shows as "duplicated" in ifconfig. No big deal, I try to set the address manually (while keeping the same prefix), but no dice. For every address I manually set it to, it says that the address is already in use.

en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
    inet6 <link-local address> prefixlen 64 scopeid 0x5
    inet6 <global address 1> prefixlen 64 duplicated autoconf 
    inet6 <global address 2> prefixlen 64 duplicated autoconf temporary 
    media: autoselect
    status: active

The funny thing is, when directly observing the traffic con the network using tcpdump, I can see the neighbor solicitation when the machine tries to acquire the IP address, but no responses are recorded!

23:25:54.808324 IP6 <router link-local> > ff02::1: ICMP6, router advertisement, length 56
23:26:01.360319 IP6 <router link-local> > ff02::1: ICMP6, router advertisement, length 56
23:26:02.696644 IP6 <machine link-local> > ff02::2: ICMP6, router solicitation, length 16
23:26:02.702210 IP6 <machine link-local> > ff02::2: ICMP6, router solicitation, length 16
23:26:04.386366 IP6 <router link-local> > ff02::1: ICMP6, router advertisement, length 56
23:26:04.386676 IP6 :: > ff02::1:ff99:be5a: ICMP6, neighbor solicitation, who has <machine global address 1> length 24
23:26:04.386677 IP6 :: > ff02::1:ffa8:2700: ICMP6, neighbor solicitation, who has <machine global address 2> length 24
23:26:04.387441 IP6 :: > ff02::1:ff99:be5a: ICMP6, neighbor solicitation, who has <machine global address 1> length 24
23:26:04.387776 IP6 :: > ff02::1:ffa8:2700: ICMP6, neighbor solicitation, who has <machine global address 2> length 24
23:26:10.078898 IP6 <router link-local> > <machine link-local>: ICMP6, neighbor solicitation, who has <machine link-local>, length 32
23:26:10.078987 IP6 <machine link-local> > <router link-local>: ICMP6, neighbor advertisement, tgt is <machine link-local>, length 24
23:26:12.712866 IP6 <router link-local> > ff02::1: ICMP6, router advertisement, length 56
23:26:15.059605 IP6 <machine link-local> > <router link-local>: ICMP6, neighbor solicitation, who has <router link-local>, length 32
23:26:15.060925 IP6 <router link-local> > <machine link-local>: ICMP6, neighbor advertisement, tgt is <router link-local>, length 24
23:26:21.064025 IP6 <router link-local> > ff02::1: ICMP6, router advertisement, length 56
23:26:25.014812 IP6 <router link-local> > ff02::1: ICMP6, router advertisement, length 56

I'm on a MacBook late 2009 with MacOS X 10.8.2. Anyone having similar issues?

share|improve this question
    
What model/firmware of router are you using? –  Michael Hampton Feb 13 '13 at 1:10
    
TP-LINK TD-W8968, but I'm pretty sure it's not a router issue... Firmware is the newest one available. –  Aljaž Srebrnič Feb 13 '13 at 8:12
    
That looks like a bug on the Mac OS side. Which OS are you using? –  Sander Steffann Feb 13 '13 at 8:30
    
MacOS 10.8.2, but other machines with 10.8.2 work fine. –  Aljaž Srebrnič Feb 13 '13 at 21:11
    
By the way: it works perfectly via Ethernet. –  Aljaž Srebrnič Feb 28 '13 at 10:48

1 Answer 1

up vote 0 down vote accepted

Actually, it looks like the issue is a result of the IPv6 implementation on my router. See this post:

I have bought this router. It is indeed possible to set up a fake 6rd connection and configure radvd so that it works for wired clients. However, this router has a bug that makes IPv6 totally unusable over wi-fi. Namely, when a wireless device broadcasts a duplicate address detection packet, the router resends it (as unicast - and this is the bug) to all associated wireless stations, including the one that sent it. As this is a unicast packet, the original station thinks: oops! my link-local address has a duplicate! and my SLAAC-configured address is a duplicate!

share|improve this answer
    
I'm pretty sure it is a router issue :) –  Michael Hampton Sep 23 at 18:01

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