I noticed when trying to reach www.freebsd.org the last week on a mac that it took forever, just sitting there spinning on an empty page. But on the same network in loaded right away on a Windows XP system. I thought that was rather odd, but moved on and didn’t think about it again until last night. I tried it again and noticed the same problem, using any browser on the mac it never loaded, on Windows XP showed up right away.
That’s when a little inspiration showed up. I knew that www.freebsd.org was also available via IPv6, I wonder if Mac OS X was trying to reach it via IPv6 first. If it was then it would never succeed as my DSL provides IPv4 and I don’t have a IPv6 tunnel setup. First I confirmed that www.freebsd.org had an IPv6 address, host www.freebsd.org provided this:
[sourcecode highlight=”2″]
www.freebsd.org has address 69.147.83.33
www.freebsd.org has IPv6 address 2001:4f8:fff6::21
www.freebsd.org mail is handled by 0 .
[/sourcecode]
The second line there confirmed that there was indeed an IPv6 DNS address for www.freebsd.org.
Next was a quick trip to the network preferences on the mac. Click the ‘Advanced’ button for your network connection and under the TCP/IP section you’ll see an option labeled ‘Configure IPv6’. Mine was set to ‘Automatically’, which I then changed to ‘Off’. Click ‘OK’ then ‘Apply’. That turned off IPv6 support for my network connection on the mac.
And sure enough www.freebsd.org loaded up right away again after that.
If you aren’t using IPv6 on your network then it’s probably worth just turning it off. I’m rather surprised that I didn’t run into this sooner. I guess there aren’t that many websites out there advertising IPv6 addresses.
Update: I noticed that us2.php.net has an IPv6 address listed as well, which explains why I’d had problems loading that site too.