[OSX-Users] Re: HTC Integration

[Tim Chown]

Hey Hugh,

That issue is probably rogue IPv6 router advertisements.   If you run an ifconfig you should see 'normal' IPv4 and IPv6 addresses in use.   If you see an IPv6 address starting '2002:...' (the correct one is 2001:630:...) there's some device (incorrectly) issuing IPv6 router advertisements, and your Mac interprets the messages as indicating a valid (but bad) router to use.   Other operating systems have address selection mechanisms that help them avoid falling prey to this, but OS X is vulnerable. 

It's a little like the rogue DHCPv4 server problem for IPv4, except most switch/router devices support DHCPv4 'snooping' to allow admins to configure which ports genuine DHCPv4 responses should be seen on.   The vendors are catching up with a similar mechanism for IPv6 for RA snooping.    

The irony is that both rogue RAs and rogue DHCPv4 servers are often caused by the same thing - Windows Internet Connection Sharing (ICS), which turns a Windows box into a NAT and IPv6 (6to4) router, usually on its wireless interface.   Great if you really want to share connections, but really bad if you don't :)    The double irony (from Marcus' post) is that we have seen Desire HDs doing this too with their connection sharing capability.

Anyway, it's a problem with IPv6 on shared networks, it's mainly noticed by Mac users due to Apple's rather lacking implementation.   Apple don't implement IPv6 address selection, DHCPv6 or source specific multicast, for example.

As it happens I have an RFC (6104) being published this week on the issue!

Tim

On 23 Feb 2011, at 20:59, Hugh Glaser wrote:

> Don't know if it is relevant, but
> When I was in B32 coffee room a couple of weeks ago I was having a lot of difficulty with the network.
> That is not very unusual, as my Mac seems to be temperamental.
> But it was worse than normal, and it seemed to be an issue for mac users.
> I was then told that switching off IPv6 would help, and this seemed to be part of the folklore.
> I did ask if it had been reported :-)
> And just in case it is also relevant, there has been or at least used to be an issue in the AG room wifi, as people seem to think they can't do demos that make heavy use unless wired.
> I did ask if that had been reported as well :-)
> Cheers
> 
> On 23 Feb 2011, at 20:47, Tim Chown wrote:
> 
>> Marcus,
>> 
>> Can you report what the IPv6 configuration on your device is?    Is it getting IPv6 config info correctly?
>> 
>> Are you sure the IPv6 module is loaded?   Older Desire devices have IPv6 support but the module isn't loaded by default.
>> 
>> Which services are causing the problems?
>> 
>> iOS certainly has working IPv6 support on the wireless (not 3G) interface.     A simple test is whether the www.kame.net turtle dances :)    On my iPhone4 I have no problems accessing web, imap and other services that return AAAA records, and in same cases IPv6 transport is used.
>> 
>> Would be nice to find the problem rather than just turn it off...
>> 
>> Tim
>> 
>> On 23 Feb 2011, at 15:21, Marcus Cobden wrote:
>> 
>>> If you have any troubles accessing ECS services while on campus IPv6 may be your problem.
>>> 
>>> I can't comment on the Desire HD, but my Hero (running Froydvillain) fails at DNS queries.
>>> 
>>> While on campus the DNS servers will give you IPv6 AAAA records which android seems to fail to parse, returning a 'null'.
>>> If you get a terminal emulator and do an nslookup for an appropriate address (ipv6.google.com) you'll get a null address in the result (you may need root for this).
>>> 
>>> I've had to specify the ECS mailservers by IP and ok the SSL certificate mismatch.
>>> I'm using IMAP and the k9 mail app, so I can't really comment on exchange support.
>>> 
>>> Marcus.
>>> 
>>> On 23 Feb 2011, at 12:11, Hugh Glaser wrote:
>>> 
>>>> Hi,
>>>> I've had enough of how slow my iPhone 3G has become, so time to upgrade...
>>>> 
>>>> Looking at the HTC Desire HD.
>>>> I am assuming I will be able to make phone calls, but there are one or two other things I use my phone for.
>>>> Being a OSX user for my main machine, is there anything I should know?
>>>> (I have looked on the web, but it is hard to find answers as good as I might get here :-) )
>>>> 
>>>> In particular, I want to listen to podcasts that come to me via iTunes - what's the deal?
>>>> Does the camera appear as a camera to iPhoto OK?
>>>> Don't suppose my Safari bookmarks/history will get shared, for the rare occasion I surf on such small screens?
>>>> Any obvious gotchas?
>>>> 
>>>> Also (although not mac related, but I hope you don't mind me asking), does it's mailer do Exchange OK?
>>>> 
>>>> Thanks
>>>> Hugh
>>> 
>>> 
>> 
>> 
> 
> -- 
> Hugh Glaser,  
>              Intelligence, Agents, Multimedia
>              School of Electronics and Computer Science,
>              University of Southampton,
>              Southampton SO17 1BJ
> Work: +44 23 8059 3670, Fax: +44 23 8059 3045
> Mobile: +44 78 9422 3822, Home: +44 23 8061 5652
> http://www.ecs.soton.ac.uk/~hg/
> 
> 
>