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smagnuson
2006-12-21, 10:25
Hello,

I'm using a SB3 in bridge mode as follows:

Internet <--> Linksys WRT54GS <-[wireless]-> SB3 <-[wired]-> Mac Mini

I'm running 6.5.0 SlimServer on the Mac Mini. Everything works fine except for IPv6. I can pass unicast and multicast IPv6 traffic from the mini towards the Internet through the SB3 bridge fine (I see the traffic using tcpdump on the WRT), but only multicast IPv6 traffic passes from the WRT through the SB3 bridge to the Mac Mini. I know this because tcpdump on the mini shows only traffic destined to IPv6 multicast addresses (ff02::...) arriving on the mini. Unicast IPv6 traffic is dropped at the SB3 bridge. If the mini is connected directly (wired) to an ethernet port on the WRT, IPv6 unicast and multicast work fine in both directions. All IPv4 traffic works fine in both directions, of course.

Why don't I just use the mini's Airport Extreme card and connect to the WRT wirelessly? Because there is a known problem with Airport Extreme cards and Linksys routers - the wireless connection drops once a day or so and manual intervention is required to bring it back up. And, yes, IPv6 unicast and multicast work fine in both directions when the mini talks wirelessly directly to the WRT (other than the irritating random connection drop problem).

Anyone else out there running IPv6 through the SB3 bridge?

Regards,

Steve

Mark Lanctot
2006-12-21, 11:06
This sounds like an obscure enough issue and you have it documented so well that I'd post a bug if I were you.

http://bugs.slimdevices.com

You'll have to create an account.

smagnuson
2006-12-21, 13:03
Mark,

Thanks for the prompt reply. I'll follow your advice, but I don't hold out too much hope that it'll be fixed. I did a bug search just now and found "Bug 364: IPV6 Support for SB" with a status of "Resolved: WONTFIX".

Nevertheless, the problem I'm having seems to be a genuine issue with the bridging firmware. So, I'll open a bug report anyway.

Steve

Mark Lanctot
2006-12-21, 13:05
Mark,

Thanks for the prompt reply. I'll follow your advice, but I don't hold out too much hope that it'll be fixed. I did a bug search just now and found "Bug 364: IPV6 Support for SB" with a status of "Resolved: WONTFIX".

Nevertheless, the problem I'm having seems to be a genuine issue with the bridging firmware. So, I'll open a bug report anyway.

Steve

Hmm - well with IPv6 slowly being deployed, the player will have to support it sooner or later.

smagnuson
2006-12-21, 13:12
I just opened bug 4612. We'll see what happens.

Steve

Ben Sandee
2006-12-21, 13:19
On 12/21/06, smagnuson <
smagnuson.2j6m6b1166731501 (AT) no-mx (DOT) forums.slimdevices.com> wrote:
>
>
> Mark,
>
> Thanks for the prompt reply. I'll follow your advice, but I don't hold
> out too much hope that it'll be fixed. I did a bug search just now and
> found "Bug 364: IPV6 Support for SB" with a status of "Resolved:
> WONTFIX".


That bug was filed against the SB1 generation of hardware, and it was marked
WONTFIX because the hardware wasn't beefy enough. The SB2 and SB3 are much
more powerful, so it's worth filing another enhancement request.
Particularly since it is intended to be used as a bridge (the SB1 wasn't).

Ben

smagnuson
2006-12-22, 10:07
I thought a packet trace might help, so I updated bug report 4612 with the following information (posting here also for those of you who are interested):

Scenario:

Internet <----> WRT54GS <--[wireless]--> SB3 <--[wired]--> Mac mini

Mac addresses:
WRT54GS wireless interface: 00:12:17:19:79:c1
SB3 Bridge: 00:04:20:06:3D:CD
Mac Mini: 00:16:cb:a7:27:8a

Upon executing "ping6 www.kame.net", and after successful DNS resolution (using
IPv4), the mini sends out a neighbor soliciation looking for it's router (Note
this is sent to a IPv6 multicast address, which is mapped to a MAC multicast
address 33:33:ff....). This is as seen using tcpdump on the mini:

08:35:42.043139 00:16:cb:a7:27:8a > 33:33:ff:19:79:c1, ethertype IPv6 (0x86dd),
length 86: 2001:618:400:29a8:216:cbff:fea7:278a > ff02::1:ff19:79c1: ICMP6,
neighbor solicitation, who has fe80::212:17ff:fe19:79c1, length 32


The WRT sees (using tcpdump on WRT) this packet (Note WRT sees packet arriving
from SB3's bridge MAC addr):

08:35:42.186342 00:04:20:06:3d:cd > 33:33:ff:19:79:c1, ethertype IPv6 (0x86dd),
length 86: 2001:618:400:29a8:216:cbff:fea7:278a > ff02::1:ff19:79c1: icmp6:
neighbor sol: who has fe80::212:17ff:fe19:79c1

WRT immediately replies with a unicast IP neighbor advertisement (the reply) to
the mini's MAC addr:

08:35:42.186790 00:12:17:19:79:c1 > 00:16:cb:a7:27:8a, ethertype IPv6 (0x86dd),
length 86: fe80::212:17ff:fe19:79c1 > 2001:618:400:29a8:216:cbff:fea7:278a:
icmp6: neighbor adv: tgt is fe80::212:17ff:fe19:79c1


This unicast IPv6 neighbor advertisement never arrives at the mini, so I assume
it is dropped by the SB3 bridge.