Ok so if i build a membership website in PHP5 where people login etc, do i need to use this Pear package?: http://pear.php.net/package/Net_IPv6 What would happen if i did not use the PEAR package, and a ipv6 user visited my php website, will they get an error because PHP5 on it's own doesn't support IPv6 addresses? By the way, the php function gethostbyname only works with IPv4 addresses: http://www.php.net/manual/en/function.gethostbyname.php
Not too many people have IPv6 yet (that I know of), so I'd just start working on the site regardless. If you do encounter people that need IPv6 support, your first stop is setting up the router for your webserver, as well as updating the networking software (before you even get to the PHP module).