In reply to a post by billford:

It certainly provides some justification for Apple to cause OS X to prefer IPv4 to IPv6 when they're both available

This is no longer (automatically) the case.

In response, operating systems started preferring IPv4 connectivity over tunneled IPv6 connectivity. In OS X, this change was made in the 10.6.5 update. But users waiting for applications to realize that IPv6 connections aren't going anywhere isn't exactly up to Apple's user experience standards. So with 10.6 Snow Leopard, Apple further introduced a mechanism that tried to determine whether IPv4 or IPv6 is faster, and then prefer to use that protocol.

During most of the reign of Snow Leopard, this "happy eyeballs" approach had an unexpected side effect. Sometimes sites wouldn't load at all when running IPv6-only, because the IPv6 connectivity was deemed insufficient. However, this issue seems to have been fixed in the 10.6.8 update. In 10.7 Lion, the eyeballs were made even happier because now the system will try to talk to a remote destination that has IPv6 and IPv4 over both protocols and then settle on the one that is fastest. What I see a lot is that a first connection uses IPv6, and then subsequent ones use IPv4, as my (tunneled) IPv6 at home is somewhat slower than my IPv4.

- http://arstechnica.com/apple/2012/05/the-future-is-f...

Edited by xela (Thu 10-Apr-14 10:32:49)

In reply to a post by jelv:

Could anyone who has IPv6 available compare the speed of download of the images over IPv6 and IPv4 please:

...

It's old news now but the IPv6 link is way (10x, 20x?) slower for me as well.

In reply to a post by RobertoS:

IPv6 automatically then.

That's how it should be, but it can depend on the OS and browser. With OS X and Safari it's a matter of luck and I think Windows can have a mind of its own on occasion (no experience there).

Linux appears to behave properly- every time I've tried a test with the Linux box (Firefox) I've got the IPv6 one.

That's more or less how I understood it, thanks for the link.

The point is that it's not the recommended behaviour� your linked article raises the point that I've always maintained:

It would be great if Apple could add the mechanism that lets system administrators change the rules that govern IPv4 vs IPv6 preference (the RFC 3484 policy table), something already possible in other operating systems.

But then, Apple always know what is best for their users� which is why my next systems will almost certainly be Linux!

it will say in corner of speedtest window in a yellow box ipv6.

Also it doesnt auto detect isp on the ipv6 tester another giveaway.

Regarding my last post, turns out was another gateway issue, after I hopped gateways I had full speeds again, getting sick of gateway hopping for performance.

personally I dont agree with ipv6 preference. I have come across a few sites that advertise dual stack but dont load on ipv6 as if they testing or something, the nasa example is another issue I come across where ipv6 connectivity is much lower priority due to the low amount of users on it. Also when geographical access points for things CDN's the ipv6 side has less access points so more likely to have ligher latency.

The ipv6 preference is also effectively a barrier to isps as well because they know if they roll something out that doesnt work right end users will notice due to operating systems and software trying ipv6 first.

But it is what it is, the standards are ipv6 should be preffered.

I don't particularly mind software vendors using non-standard methods to help users especially when, like now, it's something fairly new and not widespread.

But I object strongly to not being able to over-ride them if I want to (and take the consequences ).

In windows it can be done but not in the GUI. I made a batch script to toggle the preference, it assigns new values to the prefixpolicy so ipv4 is weighted higher.

Firefox has a plugin called 4 or 6 which allows overiding, but thats limited to just the browser of course.

FreeBSD can do it with a one line config change.

Linux if I remember right is similiar to windows fiddling with precedence settings.

In reply to a post by Chrysalis:

Linux if I remember right is similiar to windows fiddling with precedence settings.

After a bit of googling� yes, you can change the preferences but the default seems to be to prefer IPv6 if both are available. Which fits with what I've seen so far (tho' I wouldn't claim my testing has been exhaustive!).

yeah have to be careful as well.

When I first enabled ipv6 on my own mail server, my emails to gmail started been blocked as I forgot to add a rdns record to the ipv6, was been lazy so I set ipv4 precedence but then the smtp server internally was still preffering ipv6 as numerous software will have internal rules to prefer ipv6 as well, in the end I just configured my ipv6 properly, rdns, headers etc. and then set it back to preference.