There are cases where IPv6 is messing things, especially with some Wifi base station, which, are not supporting IPv6 properly or at all.
So, when a device is not supporting IPv6, there is nothing worse than connecting to it and trying first to get all the IPv6 stuff from it. Initial handshake is then a mess, takes time and sometimes leads to an error.
But, Internet is pushing IPv6 more and more and new OSes are no more offering an easy way to get it OFF.
If you a are running latest version of OS X Lion, you have noticed that you can not, by default, select to turn IPv6 off...
So, here is a quick "How-to" that will show you how to disable IPv6 from your Mac running OS X Lion:
First, open a Terminal (Applications > Utilities > Terminal.app) and run the following command:
networksetup -listallnetworkservicesThis will display all network services configured / accessible on your Mac.
Select from the above list the interface / network on which you want to disable IPv6 and the issue the following command (still in Terminal):
networksetup -setv6off EthernetNow, if you open System Preferences > Network you can see that IPv6 is turned off for the Ethernet interface. You can do the same for Wifi and even VPN.
networksetup -setv6on Ethernet